- Osteology is the scientific study of bones, practiced by osteologists. A subdiscipline of anatomy, anthropology, and paleontology, osteology is a detailed study of the structure of bones, skeletal elements, teeth, microbone morphology, function, disease, pathology, the process of ossification (from cartilaginous molds), the resistance and hardness of bones (biophysics), etc. often used by scientists with identification of vertebrate remains with regard to age, death, sex, growth, and development and can be used in a biocultural context. Osteologists frequently work in the public and private sector as consultants for museums, scientists for research laboratories, scientists for medical investigations and/or for companies producing osteological reproductions in an academic context.
- The clavicle or collarbone is a long bone that serves as a strut between the shoulder blade and the sternum or breastbone. There are two clavicles, one on the left and one on the right. The clavicle is the only long bone in the body that lies horizontally.
- also known as shoulder bone, shoulder blade, wing bone or blade bone, is the bone that connects the humerus with the clavicle. Like their connected bones the scapulae are paired, with the scapula on either side of the body being roughly a mirror image of the other.
- The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes.
- The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It runs parallel to the radius, the other long bone in the forearm, and is the larger and longer of the two.
- The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The radius is shorter and smaller than the ulna.
- The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term “carpus” is derived from the Latin carpus and the Greek καρπός (karpós), meaning “wrist”. In human anatomy, the main role of the wrist is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, and the mobility of individual carpal bones increase the freedom of movements at the wrist
- the metacarpal bones or metacarpus, form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist which forms the connection to the forearm. The metacarpal bones are analogous to the metatarsal bones in the foot.
- The phalanges are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones.
- The scaphoid bone is one of the carpal bones of the wrist. It is situated between the hand and forearm on the thumb side of the wrist (also called the lateral or radial side). It forms the radial border of the carpal tunnel. The scaphoid bone is the largest bone of the proximal row of wrist bones, its long axis being from above downward, lateralward, and forward. It is approximately the size and shape of a medium cashew.
- The lunate is a crescent-shaped carpal bone found within the hand. The lunate is found within the proximal row of carpal bones. Proximally, it abuts the radius. Laterally, it articulates with the scaphoid, medially with the triquetral, and distally with the capitate.
- The triquetrum refers to a part of the wrist known as the triquetral bone. Specifically, the bone is part of the carpus, a group of eight wrist bones. The triquetrum and other bones in the carpus are located between the two major bones in the forearm, the radius and ulna
- The pisiform is a sesamoid bone, with no covering membrane of periosteum. It is the last carpal bone to ossify. The pisiform bone is a small bone found in the proximal row of the wrist (carpus). It is situated where the ulna joins the wrist, within the tendon of the flexor carpi ulnaris muscle.
- Encloses the arm
- Superiorly: continuous with the deltoid, pectoral and axillary fascia
- Inferiorly: continuous with antebrachial fascia and attaches the epicondyles of the humerus
- the cephalic vein is a superficial vein in the arm. It communicates with the basilic vein via the median cubital vein at the elbow and is located in the superficial fascia along the anterolateral surface of the biceps brachii muscle.
- The basilic vein is a large superficial vein of the upper limb that helps drain parts of the hand and forearm.
The anterior axioappendicular muscles are the:
- Pectoralis major
- Pectoralis minor
- Serratus anterior
- The scapulohumeral muscles are a group of seven muscles that connect the humerus to the scapula. They are amongst the muscles that act on and stabilise the glenohumeral joint in the human body.
- The axilla is the space in the interval marking the junction of the upper arm and the chest wall. It is a key area because many important neurovascular structures pass through it. It is pyramidal in shape.
- the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa. As one of the four muscles of the rotator cuff, the main function of the infraspinatus is to externally rotate the humerus and stabilize the shoulder joint.
- Teres Minor is a narrow muscle which lies below infraspinatus, above teres major and triceps brachii, and deep to deltoid. It is one of the four muscles which comprise the Rotator Cuff.
- The deltoid is a large muscle responsible for lifting the arm and giving the shoulder its range of motion. It is located in the uppermost part of the arm, at the shoulder. Tendons attach the deltoid to the collarbone, shoulder blade, and upper arm.
- is a relatively small muscle of the upper back that runs from the supraspinatous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator cuff muscles and also abducts the arm at the shoulder.
- Teres major is a small muscle that runs along the lateral border of the scapula. It forms the inferior border of both the triangular space and quadrangular space.
- The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.
- The brachial plexus is a network (plexus) of nerves (formed by the ventral ramus of the lower four cervical nerves and first thoracic nerve (C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit.
- Network of nerves supplying the upper linb
- Originates in the posterior triangle of the neck and passes to the axilla
Boundaries of Axilla
The anterior wall is formed by the pectorales major and minor. The posterior wall is formed by the subscapularis above, the teres major and latissimus dorsi below. On the medial side are the first four ribs with their corresponding intercostales, and part of the serratus anterior.
- the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb.
- Direct continuation of the subclavian artery starting at lateral border of rib 1 and ends at interior border of the teres major.
Superior Thoracic Artery
- is a small artery located near the armpit in humans. It normally arises from the first division of the axillary artery, but may arise from the thoracoacromial artery, itself a branch of the second division of the axillary artery.
- is a short trunk that arises from the second part of the axillary artery, its origin being generally overlapped by the upper edge of the pectoralis minor.
Lateral Thoracic Artery
- is a blood vessel that supplies oxygenated blood to the lateral structures of the thorax and breast.
- The subscapular artery, the largest branch of the axillary artery, arises from the third part of the axillary artery at the lower border of the subscapularis muscle, which it follows to the inferior angle of the scapula, where it anastomoses with the lateral thoracic and intercostal arteries, and with the descending branch of the dorsal scapular artery
Anterior Circumflex Humeral Artery
- The anterior humeral circumflex artery runs horizontally, beneath the coracobrachialis and short head of the biceps brachii muscle, in front of the neck of the humerus. On reaching the intertubercular sulcus, it gives off a branch which ascends in the sulcus to supply the head of the humerus and the shoulder-joint.
Posterior Circumflex Humeral Artery
- arises from the third part of axillary artery at the lower border of the subscapularis, and runs posteriorly with the axillary nerve through the quadrangular space.
Apical lymph nodes
- An apical group of six to twelve glands is situated partly posterior to the upper portion of the Pectoralis minor and partly above the upper border of this muscle. Its only direct territorial afferents are those that accompany the cephalic vein, and one that drains the upper peripheral part of the mamma.
Anatomy of the Arm
Two Mascular Compartment:
- Lateral Intermuscular Septum – The lateral intermuscular septum extends from the lower part of the crest of the greater tubercle of the humerus, along the lateral supracondylar ridge, to the lateral epicondyle; it is blended with the tendon of the deltoid muscle, gives attachment to the triceps brachii behind, and to the brachialis, brachioradialis, and extensor carpi radialis longus muscles in front. It is perforated by the radial nerve and profunda branch of the brachial artery.
- Medium Intermuscular Septum- The medial intermuscular septum, is thicker than the lateral intermuscular septum. It extends from the lower part of the crest of the lesser tubercle of the humerus below the teres major, and passes along the medial supracondylar ridge to the medial epicondyle; it is blended with the tendon of the coracobrachialis, and gives attachment to the triceps brachii behind and the brachialis in front.
- is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. While the biceps crosses both the shoulder and elbow joints, its main function is at the elbow where it flexes the forearm and supinates the forearm. Both these movements are used when opening a bottle with a corkscrew: first biceps unscrews the cork (supination), then it pulls the cork out (flexion)
- Supinates forearm and once supinated flexes elbow joint and flexes shoulder
- is a muscle in the upper arm that flexes the elbow joint. It lies deeper than the biceps brachii, and makes up part of the floor of the region known as the cubital fossa. The brachialis is the prime mover of elbow flexion.
- Flexes elbow joint
- The coracobrachialis muscle is found at the upper and medial part of the arm. Originating from the scapula and inserting into the humerus, this muscle allows you to flex and adduct the arm. In addition, it also stabilizes the joint itself.
- Flexes and adduct shoulder joint
- The cubital fossa is an area of transition between the anatomical arm and the forearm. It is located as a depression on the anterior surface of the elbow joint.
- Shallow triangular depression to the elbow joint
- The pronator teres is a muscle (located mainly in the forearm) that, along with the pronator quadratus, serves to pronate the forearm (turning it so that the palm faces posteriorly when from the anatomical position).
- Pronates and flexes forearm
Flexor Carpi Radialis
- Flexor carpi radialis is a muscle of the human forearm that acts to flex and (radial) abduct the hand. The Latin carpus means wrist; hence flexor carpi is a flexor of the wrist.
- Flexes and abducts hand at wrist
- Palmaris longus is a muscle that can be found partly in the forearm, wrist, and hand. It has two functions. A minor function is to help flex the hand at the wrist. A more major function is to tense and tighten the palmar aponeurosis.
- Flexes hand at wrist and tenses palmar aponeurosis
Flexor Carpi Ulnaris
- Flexor carpi ulnaris muscle (FCU) is the most medial flexor muscles in the superficial compartment of the forearm. It can adduct and flex the wrist at the same time; acts in tandem with FCR to flex the wrist and with the extensor carpi ulnaris to adduct the wrist.
- Flexes and adducts hand at wrist
Flexor Digitorum Profundus
- The flexor digitorum profundus is a muscle in the forearm of humans that flexes the fingers (also known as digits). It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm.
- Flexes hand at wrist joint
- Flexes distal interphalangeal joint
Flexor Pollicis Longus
- Is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus.
- Flexes wrist
- Flexes interphalangeal and metacarpophalangeal joints of first digit
- The pronator quadratus is a muscle that is near the lower part of the radius. Its function is to rotate the forearm and keep the proper distance and rotation between the ulna and radius. It is considered a deep muscle and is a quadrangle shape.
- Pronates forearm
Flexor Digitorum Superficialis
- is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints. It is in the anterior compartment of the forearm.
- The brachioradialis is a muscle of the forearm that flexes the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm.
Extensor Carpi Radialis Longus
- The extensor carpi radialis longus is a muscle that helps move the hand. It also facilitates movement at the wrist. It is involved in extending and abducting the hand at the wrist joint.
- is longer and thinner than its brevis counterpart.
Extensor Carpi Radialis Brevis
- is a muscle in the forearm that acts to extend and abduct the wrist. It is shorter and thicker than its namesake extensor carpi radialis longus which can be found above the proximal end of the extensor carpi radialis brevis.
- Extend and abduct wrist
- is a superficial, long muscle of the forearm that belongs to the posterior muscle group, lying in the first or superficial layer.
Extensor Digiti Minimi
- is a two joint muscle. It acts as an extensor in both joints. It extends the wrist, which means it moves the back of the hand toward the back of the forearm. It also extends the little finger, which means it straightens the little finger from a fist.
Extensor Carpi Ulnaris
- the extensor carpi ulnaris is a skeletal muscle located on the ulnar side of the forearm. It acts to extend and adduct at the carpus/wrist from anatomical position. Being an extensor muscle, extensor carpi ulnaris is on the posterior side of the forearm.
Abductor Pollicis Longus
- the abductor pollicis longus (APL) is one of the extrinsic muscles of the hand. As the name implies, its major function is to abduct the thumb at the wrist. Its tendon forms the anterior border of the anatomical snuffbox.
Extensor Pollicis Longus
- the extensor pollicis longus muscle (EPL) is a skeletal muscle located dorsally on the forearm. It is much larger than the extensor pollicis brevis, the origin of which it partly covers and acts to stretch the thumb together with this muscle.
Extensor Pollicis Brevis
- is located on the dorsal side of the forearm
- It is connected with the extensor pollicis longus to make up the interosseous membrane. It inserts at the base of the proximal phalanx of the thumb. This muscle also forms the radial side of the anatomical snuff box at the wrist.
- The supinator is a broadly-shaped muscle in the superior and posterior compartment of the forearm, It curves around the upper third of the radius and consists of two layers of fibres. In between these layers lies the deep branch of the radial nerve.
- Supination of forearm
- Extensor indicis muscle is labeled in purple. In human anatomy, the extensor indicis
is a narrow, elongated skeletal muscle in the deep layer of the dorsal forearm, placed medial to, and parallel with, the extensor pollicis longus. Its tendon goes to the index finger, which it extends.
- Extends wrist
Palmer Aspect of the Hand
- The palmar aspect of the hand can be divided into a number of compartments
- A layer of fascia spreads over the hand as a continuation of the forearm fascia
- The opponens pollicis is a small, triangular muscle in the hand, which functions to oppose the thumb. It is one of the three thenar muscles, lying deep to the abductor pollicis brevis and lateral to the flexor pollicis brevis.
Abductor Pollicis Brevis
- The abductor pollicis brevis muscle is located in the hand between the wrist and the base of the thumb. It originates from the flexor retinaculum and the tubercles of the scaphoid and trapezium bones. It inserts in the outer side of the base of the proximal phalanx of the thumb.
Flexor Pollicis Brevis
- The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles. It has both a superficial part and a deep part.
- The carpal tunnel is a narrow passageway in the wrist, about an inch wide. The floor and sides of the tunnel are formed by small wrist bones called carpal bones. The carpal tunnel protects the median nerve and flexor tendons that bend the fingers and thumb.
- The long tendons of extrinsic muscles enter the hand through the carpal tunnel
- Formed by the flexor retinaculum and the concave carpal bones
- the dorsal interossei (DI) are four muscles in the back of the hand that act to abduct (spread) the index, middle, and ring fingers away from hand’s midline (ray of middle finger) and assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index, middle and ring fingers.
- the palmar or volar interossei (interossei volares in older literature) are three small, unipennate muscles in the hand that lie between the metacarpal bones and are attached to the index, ring, and little fingers.
- They are smaller than the dorsal interossei of the hand.
- Passes through anterior compartment deep to pronator teres and runs alongside flexor carpi ulnaris with the ulnar nerve running medial
- The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspect of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial artery. It is palpable on the anterior and medial aspect of the wrist.
- Passes through anterior compartment deep to brachioradialis. It exits the forearm by passing around lateral wrist to enter anatomical snuff box in the hand.
Deep Palmar Arch
- is an arterial network found in the palm. It is usually formed mainly from the terminal part of the radial artery, with the ulnar artery contributing via its deep palmar branch, by an anastomosis.
- Gives rise to three palmar metacarpal arteries that anastomose with the common palmar digital arteries
- The sternoclavicular joint or sternoclavicular articulation is the joint between the manubrium of the sternum and the clavicle bone. It is structurally classed as a synovial saddle joint and functionally classed as a diarthrosis and multiaxial joint.
- is a ligament of the shoulder girdle. It is short, flat, and rhomboid in form.
- Connects the sternal end of the clavicle to the first rib, prevents excessive superior movement
- The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle.
- Joint between the acromial end of the clavicle and the acromian of the scapula
- The coracoclavicular ligaments are strong supports between the lateral end of the clavicle and the coracoid process of the scapula. On each side, they are sited medially and inferior to the acromioclavicular joints.
- Anchors the clavicle to the coracoid process and the augments the AC joint
- The shoulder joint (glenohumeral joint) is a ball and socket joint between the scapula and the humerus. It is the major joint connecting the upper limb to the trunk. It is one of the most mobile joints in the human body, at the cost of joint stability.
- is a broad ligament which strengthens the upper part of the capsule of the shoulder joint.
- From coracoid process to greater tubercle of humerus
Transverse Humeral Ligament
- The transverse humeral ligament is a broad band passing from the lesser to the greater tubercle of the humerus, and always limited to that portion of the bone which lies above the epiphysial line. It converts the intertubercular groove into a canal.
- Bridges the intertubercular groove by attaching to the greater and lesser tubercles.
- Creates the channel for the long head of biceps to pass through
- The elbow joint is a complex hinge joint formed between the distal end of the humerus in the upper arm and the proximal ends of the ulna and radius in the forearm. The elbow allows for the flexion and extension of the forearm relative to the upper arm, as well as rotation of the forearm and wrist.
- he carpometacarpal joints of the fingers are synovial plane joints that serve as the articulation between the carpals and the metacarpals and allow the bases of the metacarpal bones to articulate with one another.
- The intermetacarpal joints are in the hand formed between the metacarpal bones. The bases of the second, third, fourth and fifth metacarpal bones articulate with one another by small surfaces covered with cartilage. The metacarpal bones are connected together by dorsal, palmar, and interosseous ligaments.
Musculocutaneous Nerve – Nerve Lesion
- Damage to musculocutaneous nerve
- Lesions of the nerve produce weakness of flexion at the elbow and weakness of supination. The biceps is an important supinator. There is sensory loss on the lateral side of the forearm. The brachialis muscle receives innervation from both the musculocutaneous nerve and the radial nerve.
Median Nerve Lesion
- Damage to median nerve
- is often caused by deep, penetrating injuries to the arm, forearm, or wrist. It may also occur from blunt force trauma or neuropathy
Ulnar Nerve Lesion
- Damage to ulnar nerve
- describes any pathological process capable of negatively affecting the nerve’s function.
- Inability to flex the metacarpophalangeal joints and extend the proximal and distal interphalangeal joints of digits 4 and 5
Radial Nerve Lesion
- Damage to radial nerve
- is a condition that affects the radial nerve and if damage to this nerve occurs, weakness, numbness and an inability to control the muscles served by this nerve may result.
Axillary Nerve Lesion
- Damage to axillary nerve
- is a neurological condition in which the axillary (also called circumflex) nerve has been damaged by shoulder dislocation. It can cause weak deltoid and sensory loss below the shoulder.
Long Thoracic Nerve Lesion
- Damage to long thoracic nerve
- is a shoulder condition characterized by pain and loss of shoulder movement owing to damage or injury of the long thoracic nerve. This nerve evolves from the roots of neck vertebrae (C5-C7) and supplies to serratus anterior muscle that retains the scapula bone to the chest wall.