Week 2 Anatomy

 Bony features of the clavicle

Bony Features of Clavicle

Bony Features of Clavicle


Boundaries  and contents of the axilla.

boundaries  and contents of the axilla.

boundaries and contents of the axilla.


  • Apex – posterior border clavicle, lateral border of first rib and superior border of scapula
  • Medial – serratus anterior, chest wall
  • Lateral – intertubecular grove of humerus,
  • Anteriorly – pec major and minor
  • Posterioirly – subscapularis, teres major and lat dorsi, scapula

 Smallest space when arm is fully abducted


    • mostly through inferiorly into arm.
    • Quadangular space  posteriorly – axillary nerve exits and post circumflex artery of humerus(subscapularis/teres minor above, teres major below, long head of triceps medially and humerus laterally)
    • Clavipectoral traingle – pass cephalic vein and medial and lateral pectoral nerves (clavicle, pec major and deltoid)
    • Triangular Interval – Contain radial nerve and profunda brachii artery, Borders Teras major superiorly, Long head of triceps medially, and humerus laterally.



  • Axillary artery, vein, brachial plexus, tendons of biceps and corochobrachialis, Lymph nodes



Brachial plexus.

Brachial Plexus

Musculocutaneous Nerve

  • Roots: C5, C6, C7.
  • Motor Functions: Innervates the brachialis, biceps brachii and corocobrachialis muscles.
  • Sensory Functions: Gives off the lateral cutaneous branch of the forearm, which innervates the lateral half of the anterior forearm, and a small lateral portion of the posterior forearm.

Musculocutaneous Nerve

Axillary Nerve

  • Roots: C5 and C6.
  • Motor Functions: Innervates the deltoid, teres minor and the long head of the triceps brachii.
  • Sensory Functions: Gives off the superior lateral cutaneous nerve of arm, which innervates the inferior region of the deltoid (“regimental badge area”).

Axillary Nerve

Median Nerve

  • Roots: C6 – C8 and T1.
  • Motor Functions:  Innervates most of the flexor muscles in the forearm, the thenar muscles, and the two lateral lumbrical muscles that move the index and middle fingers.
  • Sensory Functions: Gives off the palmar cutaneous branch, which innervates the lateral part of the palm, and the digital cutaneous branch, which innervates the lateral three and a half fingers on the anterior (palmar) surface of the hand.

Median Nerve

Radial Nerve

  • Roots: C5-C8 and T1.
  • Motor Functions: innervates the triceps brachii, and the extensor muscles in the posterior compartment of the forearm.
  • Sensory Functions: Innervates the posterior aspect of the arm and forearm, and the posterior, lateral aspect of the hand.

Radial Nerve


Ulnar Nerve

  • Roots: C8 and T1.
  • Motor Functions: Innervates the muscles of the hand (apart from the thenar muscles and two lateral lumbricals), flexor carpi ulnaris and medial half of flexor digitorum profundus.
  • Sensory Functions: Innervates the anterior and posterior surfaces of the medial one and half fingers, and associated palm area.

Ulnar Nerve


Sterno-clavicular joint.

  • saddle type of synovial joint but functions as a ball-and-socket joint.
  • The SC joint is divided into two compartments by an articular disc attaching to ant and post sternoclavicular ligaments.
  • These ligaments as well as costoclavicular and interclavicular ligament give the joint stability +++ so rare to displace and also shock absorbs.
  • Articular surface covered in fibrocartilage- articulates with manubrium and 1st costal cartilage.
  • Movements – elevation 60o, rotation along longitudinal axis, AP of 25-30o, circumduction.
  • Fractures most commonly post fall onto shoulder or outstretched hand – medial2/3 -lateral 1/3 junction.
  • Fracture leads to lateral end being pulled medially and inferiorly and medial end pulled superiorly
  • The superior displacement can damage suprascapular nerves and result in unopposed medial rotation of arm


Acromio clavicular joint

  • Atypical plane synovial joint
  • Articular surface covered in fibrocartilage and has an incomplete wedge articular disc.
  • Acromioclavicular ligament
  • Main stabiliser is external ligamnt – coracoclavicular ligaments – conoid and trapezoid ligaments which asre often seprated by a bursa.
  • Only passive movement occurs at this joint.
  • Lateral pec and axillary nerve, lateral supraclavicular nerve.


Branches of the axillary artery ?

  • 3 parts – first medial to pec minor, 2nd posterior to pec minor and 3rd lateral to pec minor.

Send The Lord to Say A Prayer

1 – Superior Thoracic

2 – Thoraco acromial

3 – Lateral thoracic

4 – Subscapluar

5 – Anterior circumflex of humerus

6 – Posterior Circumflex of humerus

First division – one branch: (1) Supreme Thoracic Artery Second division – two branches: (2) Thoracoacromial (with four smaller branches) A. Pectoral Branch B. Deltoid Branch C. Acromial Branch D. Clavicular Branch (3) Lateral Thoracic Artery Third division – three branches: (4) Subscapular Artery (branches to the Circumflex Scapular Artery and the Thoracodorsal Artery) (5) Anterior Humeral Circumflex Artery (6) Posterior Humeral Circumflex Artery (which passes through the quadrangular space)


Subclavian artery – related to anterior scalene

  • Starts from arch of aorta(at level of T4) or brachiocephalic trunk(behind Right SC joint). Travels between anterior and middle scalene muscles. Finishes at lateral border of first rib.
  • In relation to scalene anterior:
    • Medial – vertebral,  internal thoracic, thyrocervical trunk(very short and divides in thyroid artery, transverse cervical and suprascapular artery)
    • Posterior – costocervical trunk, sometimes dorsal scapular.
    • Lateral – sometimes dorsal scapular.


Lymph nodes of the axilla.

  • Superficial lymph follows superficial veins and deep follow deep.
  • Efferent vessels from cubital lymph nodes ascend in the arm and terminate in the humeral (lateral) axillary lymph nodes.
  • Most superficial lymphatic vessels accompanying the cephalic vein cross the proximal part of the arm and the anterior aspect of the shoulder to enter the apical axillary lymph nodes; however, some vessels previously enter the more superficial deltopectoral lymph nodes.
  • Deep lymphatic vessels, less numerous than superficial vessels, accompany the major deep veins in the upper limb and terminate in the humeral axillary lymph nodes.
  • Axillary LN clearance can endanger long thoracic nerve and result in winged scapula


Lymph drainage of the breast.

  • 75% of Lymph drain to axillary LN (pectoral) and apical LNs
  • Rest drain to internal thoracic LNs and contralateral breast and contralateral Axillar lymph nodes.