anatomy Flashcards
Synovial joint
the type of joint found between bones that move against each other, such as the joints of the limbs (e.g. shoulder, hip, elbow and knee).
Made of synovial membrane (or synovium) – a special layer of cells that lines the joint capsule and produces the synovial fluid
Axilla
Armpit region
Inferior to the glemohumeral joint
passageway by which neurovascular and muscular structurescan enter and leave the upper limb.
HOW does axilla region change shape
The apex decreases in size most markedly when the arm is fully abducted – leaving the contents of the axilla at risk of compression.
4 sides , open apex and base of the axilla
Apex – also known as the axillary inlet, it is formed by lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle.
Lateral wall– formed by intertubercular groove of the humerus.
Medial wall– consists of the serratus anterior and the thoracic wall (ribs and intercostal muscles).
Anterior wall– contains the pectoralis major and the underlying pectoralis minor and the subclavius muscles.
Posterior wall– formed by the subscapularis, teres major and latissimus dorsi.
Contents of the axilla
Axillary artery (and branches)– the main artery supplying the upper limb. It is commonly referred as having three parts; one medial to the pectoralis minor, one posterior to pectoralis minor, and one lateral to pectoralis minor. The medial and posterior parts travel in the axilla.
Axillary vein (and tributaries)– the main vein draining the upper limb, its two largest tributaries are the cephalic and basilic veins.
Brachial plexus (and branches)– a collection of spinal nerves that form the peripheral nerves of the upper limb.
Axillary lymph nodes – they filter lymphatic fluid that has drained from the upper limb and pectoral region. Axillary lymph node enlargement is a non-specific indicator of breast cancer.
Biceps brachii (short head) and coracobrachialis – these muscle tendons move through the axilla, where they attach to the coracoid process of the scapula
Passageways exiting the axilla
3 main routes
The main route of exit is immediately inferiorly and laterally, into the upper limb. The majority of contents of the axilla region leave by this method.
quadrangular space. This is a gap in the posterior wall of the axilla, allowing access to the posterior arm and shoulder area. Structures passing through include the axillary nerve and posterior circumflexhumeral artery (a branch of the axillary artery.
clavipectoral triangle, which is an opening in the anterior wall of the axilla. It is bounded by the pectoralis major, deltoid, and clavicle.The cephalic vein enters the axilla via this triangle, while the medial and lateral pectoral nerves leave.
Muscles in the shoulder - pectoralis major
Adduct and rotates the humerus
Lateral and medial pectoral nerves
Muscles in the shoulder - pectoralis minor
draws scapula anteroinferiorly, stabilizes scapula on thoracic wall
Lateral and medial pectoral nerves
muscles in the shoulder- trapezius
Rotation, retraction, elevation, depression of scapula
ACCESSORY NERVE
Lies over the rhomboid
Large triangle
Rhomboids- muscles in shoulder
Rotate scapula DOWNWARDS
Dorsal scapular nerve supply
Deltoid - muscles in shoulder
Flexion and internal rotation of arm , adduction of arm beyond 15*, external and internal rotation of arm
AXILLARY nerve
Teres major - muscles in the shoulder
Extension and inner rotation of humerus
Lower subscapular nerve
Lattimus dorsi - muscles in the shoulder
Arm internal rotation
Arm adduction and extension
Thoracodorsal nerve
Levator scapula - muscles in the shoulder
Elevate the scapula.
Anterior rami of the nerves C3 and C4,
dorsal scapular nerve (branch of the C5)
The shoulder joint - glenohumeral between scapula and humerus
Synovial joint
It is a ball-and-socket joint, formed between the glenoid fossa
Glenoid cavity is where the ball inserts
Less complete than ball and socket in hip- needs to be more stabilized – group of muscles called ROTATOR CUFF that surround the joint
Corocoid ligament = STRONG
What prevents upwards displacement of head of humerus in
Coracoacrominal arch
Rotator cuff muscles
Executors of the movements of the joint and the stabilization of the joint Subscapularis Supraspinatus Infraspinatus Teres minor
Subscapularis muscle
Allows humerus to move freely during elevation of the arm
INTERNALLY ROTATE THE ARM
Subscapular nerve (c4,c6)
Supraspinatus muscle
Abduction of the arm ( moving arm up from sides of body)
Elevates the shoulder joint out to the side
Stabilizes humeral head
Subscapular nerves c5-c6
I
Infraspinatus muscle
Externally rotates shoulder joint
Suprascapular nerve c5-c6
Teres minor muscle
Externally rotates the shoulder joint
Axillary nerve c5-c6
The elbow joint
Synovial hinge
Stabilized by ligaments – collateral ligaments of the elbow