Movement And Support Of The Shoulder Joint Flashcards
What does the CNS and the peripheral nervous system consist of?
CNS-brain(skull) and the spinal cord (vertebral column)
PERIPHERAL NERVOUS SYSTEM- cranial nerves, spinal nerves
What are somites in embryos?
They are blocks of muscle tissue that develop in pairs alongside spinal cord
Group combines to form each forelimb. Drags nerves as well and therefore the nerve supply reflects the origin
Describe the structure of the spinal nerves
Leave the spinal cord though the intervertebral foramen
They are paired left and right and branch- the dorsal branches supply dorsal structures
From what vertebrae do the brachial plexus form and where are they located?
What nerves supply the forelimb?
Ventral branches off C6,C7,C8,T1 and T2 form the brachial plexus. It is located in the axillary region
Emerging nerves supply the forelimb
What are afferent and efferent supplies?
Afferent-carry impulses from structures to brain (sensory nerve fibres)
Efferent-carry impulses from brain to structure (muscle or organ), (motor nerve fibres)
What are mixed nerves?
Consist of both motor and sensory fibres, and transmit messages in both directions at once (spinal reflexes)
What does and doesn’t the brachial plexus supply?
Supplies all intrinsic muscles Supplies some extrinsic muscles: -latissimus dorsi (retractor) -serratus ventralis (protractor and retractor) -pectoral (adductor)
Doesn’t supply:
Brachiocephalicus (protractor)
Trapezius and rhombiodeus (abductors)
What are the 3 different types of joints and what types of movement do they allow?
Fibrous-little movement
Cartilagenous-little movement
Synovial- allow a large range of movement between bones
What are the typical features of a synovial joint”
Hyaline cartilage covers articular surfaces to reduce friction and aid flexibility. It is avascular (no nerve supply) and has no nerve endings
Synovial fluid:
- sticky
- nourishes cartilage
- lubricates
Synovial membrane:
- produces synovial fluid
- physical barrier to contain fluid
Joint capsule:
- fibrous layer
- incorporates synovial membrane
- attaches around osteochondral junction
What were ligaments?
Fibrous tissue that condenses to form ligaments (DENSE FIBROUS CONNECTIVE TISSUE)
Ligaments run from bone to bone
Collateral ligaments support joints (medial and lateral)
What are the function of ligaments in relation to joints?
Support the joint and hold the bones together by restricting bone movement
Describe what flexion and extension of joints are.
Flexion- decreased angle, folded limb, non weight bearing position
Extension- increased angle, stretched limb and associated with weight bearing
What are the components of the shoulder joint?
- scapula (glenoid cavity-concave)
- humerus (head-convex)
What are the palpable landmarks of the shoulder joint
Acromion process (scapula) Greater tubercle (humerus)
What features does the shoulder joint have?
All synovial joint features except it has glunohumeral ligaments at the lateral aspect and has poorly developed collateral ligaments
What is the bicipital bursa of the shoulder joint?
- joint capsule extends into inter-tubercular groove, between greater and lesser tubercles
- wraps around tendon of origin of biceps branchii
- held in place by the transverse ligament
What lateral support does the shoulder joint have?
Supraspinatus muscle-originates at the supraspinous fossa and inserts at the greater tubercle
Infraspinatus muscle- originates at the infraspinous foss, inserts distal to the greater tubercle and abducts the shoulder . Supplied by the suprascapular nerve (MOTOR FIBRES ONLY)
What medial support does the shoulder have?
Supscapulris muscle: originates at the subscapular fossa. Inserts on the lesser tubercle, adducts the shoulder joint. Supplied by the subscapular nerve (MOTOR FIBRES ONLY)
What are shoulder extensors.
Cross cranial to shoulder joint
What type of muscle is the brachiocephalicus and what is its nerve supply like?
Brachiocephalicus-extrinsic muscle, not supplied by the brachial plexus
Describe where the biceps branchii muscle originates and inserts. What type of muscle is it and what is its nerve supply like?
Originates at the supraglenoid tubercle
Inserts at the ulnar and radial tuberosities
It’s a intrinsic muscle which is a elbow flexor and shoulder extensor
It has a motor nerve supply via the musculocutaneous nerve
What are shoulder flexors?
Cross caudal to the shoulder joint
What is the nerve supply of the latissimus dorsi nerve supply like?
From bronchial plexus
Where does the teres major originate and insert itself. Describe its nerve supply.
Where is the teres minor located?
Originates at the caudal border of the scapula
Inserts at the medial humerus
Nerve supply via the axillary nerve, motor and sensory fibres
The teres minor overlies the lateral aspect of the joint space
Where does the deltoideus muscle originate and insert? Describe its nerve supply
It has 2 heads which originate at the scapular spine and acromion process. It inserts at the lateral aspect of the humerus. It’s a intrinsic muscle
It’s nerve supply:
- axillary nerve
- mixed type (motor and sensory nerve fibres)
Describe where the triceps muscle originates and inserts and its function, as well as its nerve supply.
It has 4 heads
Has a long head and is split into 2 parts
Originates at the caudal border of the scapula and inserts on the olecranon of ulna.
It’s functions as a elbow extensor
Nerve supply:
- radial nerve
- motor and sensory fibres
