Upper Limb Flashcards
sacrum
- largest bone located at terminal part of vertebral column where it forms the posterior aspect of the bony pelvis
- remarkably thick, aids in supporting and transmitting weight of the body
- composed of 5 fused sacral vertebrae
- articulates with ilium bilaterally and with L5 at its base
sacral canal
- a continuation of the vertebral canal terminating at the sacral hiatus
- protects cauda equina and filum terminale
sacral foramina
- 4 sacral foramina located lateral to fused sacral bodies on anterior and posterior surface
- foramina decease in size with most superior foramina being the largst
- anterior and posterior rami can exit through sacral foramina
sacral cornua
- 2 bony processes
- palpable as anatomical landmark when administering injections into sacral hiatus
promontory
- upper border/base of sacrum articulates with L5 vertebral body
- promontory projects forward, decreasing the anteroposterior diameter of the pelvic brim
- in females, sacral promontory is of significant obstetric importance and is used when measuring size of pelvis
coccyx
- tailbone
- composed of 4 fused rudimentary coccygeal vertebrae which articulate with the sacrum superiorly at the sacrococcygeal joint
- smaller in size compared to sacrum
- serves as attachment site for ligaments and muscles (Ex. muscles of pelvic floor)
- a small and variable amount of flexion and extension occurs at the sacrococcygeal joint (especially when sitting)
vertebral trends
- size of vertebral body increased moving superior to inferior to support the increasing weight
- size of vertebral foramen decreases to support spinal cord diameter decreasing as spinal nerves exit
- with a smaller vertebral foramen, it is more likely a blockage to the foramen could irritate nerves in lumbar region
accessory ligaments of the vertebral column
- strong, fibrous bands of tissue that stabilize the vertebral column and protect the intervertebral discs
- 3 major ligaments involved in movements of flexion and extension: ligamentum flavum, anterior longitudinal ligament, posterior longitudinal ligament
what is the function and names of the extrinsic muscles of the back
movement of upper extremities
- latissimus dorsi
- trapezius
- rhomboid minor
- levator scapulae
- rhomboid major
latissimus dorsi
origin: T7-T12, iliac crest, inferior angle of scapula
insertion: intertubercular groove of humerus
trapezius
origin: occipital bone
insertion: scapula
rhomboid minor
origin: C7 and T1
insertion: scapula
levator sacpulae
origin: C1-4
insertion: scapula
rhomboid major
origin: T2-T5
insertion: scapula
latissimus dorsi
- broad triangular shaped muscle
- covers lumbar region and inferior portion of thoracic cage
- multiple points of origin therefore varying muscle fibre directions
- one of the largest points of origin is the broad fascial sheath
- fibres share common insertion point
- thoracolumbar fascia made from multiple crosshatched layers of collage – important role in stabilization and load transfer
- all muscle fibres of latissimus dorsi insert in the tuberucular sulcus (bicipital groove) of the humerus
erector spinae muscles
- muscle group comprised of 3 deep muscles in the back organized in parallel columns on either side of vertebral column
- from lateral to medial: iliocostalis, longissimus, spinalis
- responsible for extending (straightening) the vertebral column
what are the sections of the iliocostalis muscle
- iliocostalis cervicis
- iliocostalis thoracis
- iliocostalis lumborum
axilla
- armpit
- pyramidal shaped space between upper thorax and arm
- passageway for major nerves and blood vessels to enter and leave the upper limb
anterior wall of axilla
pectoralis major
lateral wall of axilla
intertubercular sulcus of humerus
posterior wall of axilla
subscapularis, latissimus dorsi, teres major
apex of axilla
base of neck
medial wall of axilla
serratus anterior
base of axilla
skin of armpit
axillary lymph nodes
drain breast
brachial plexus
- network of nerves that supplies motor and sensory innervation to the upper limb
- begins in neck, passes through axilla, terminal branches run through entire upper limb
what are the 5 divisions of the brachial plexus
1) roots
2) trunks
3) divisions
4) cords
5) branches
roots of the brachial plexus
- formed from ventral rami of spinal nerves C5-T11
- the 5 spinal nerve roots leave the spinal cord through the intervertebral foramen of the vertebral column
trunks of the brachial plexus
- each trunk branches into an anterior and posterior division
- nerve fibres of anterior muscles sorted from those of posterior muscles of arm, forearm and hand
divisions of brachial plexus
- each trunk branches into 6 divisions (3 anterior and 3 posterior)
- divisions correspond with anterior and posterior muscle compartments of arm, forearm and hand
cords of brachial plexus
- 3 cords (medial, lateral posterior – names by position relative to axillary artery)
branches of brachial plexus
5 terminal branches
- musculocutaneous nerve
- axillary nerve
- median nerve
- radial nerve
- ulnar nerve
musculocutaneous nerve
motor innervation of anterior compartment (flexion) of arm
axillary nerve
motor innervation to the deltoid (abduction of arm) and teres minor (lateral rotation of arm)
median nerve
motor innervation to most of the muscles of the anterior compartment of the forearm, as well as 5 of the intrinsic muscles of the hand
radial nerve
motor innervation of the posterior compartment (extension) of the arm and forearm
ulnar nerve
motor innervation of 2 muscles of the anterior compartment of the forearm and most of the anterior compartment of the hand
blood supply of upper limb
- branches of subclavian artery
radial artery
preferred pulse point at the wrist due to its relatively large size and proximity to the surface of the arm
deep venous drainage of upper limb
follows same naming and general pathway as arterial supply
- consists of an interconnected pathway that eventually forms the subclavian vein
- then continues into the brachiocephalic vein, then the superior vena cava
radial vein
drains blood from deep structure of palm and lateral aspect of forearm
ulnar vein
drains blood from deep structures of the palm and medial aspect of forearm
cephalic vein
- begins in dorsum of hand
- ascends lateral side of anterior surface of forearm and arm
- drains into axillary vein
basilic vein
begins on dorsum of hand and ascends medial side of anterior forearm and arm to become axillary vein
medial cubital vein
- in roof of cubital fossa
- connects basilic and cephalic veins
- often site of venipuncture for drawing blood
brachial vein
- receives blood from radial and ulnar veins
- drains into axillary vein
axillary vein
- continuation of basilic vein
- becomes subclavian vein as it crosses the lateral border of the 1st rib
pectoral girdle
connects upper limb to thorax
the sternum, clavicle, scapula and humerus articulate at what joints
- glenohumeral joint
- acromioclavicular joint
- sternoclavicular joint
- additional theoretical joint between scapula and thoracic cage (scapulothoracic joint)
- all movements of humerus are accompanied by movements of the scapula and clavicle
ligaments of the pectoral girdle
- acromioclavicular ligament
- coracoacromial ligament
- coracoclavicular ligament
- glenohumeral ligament
acromioclavicular ligament
- located between the acromion process of the scapula and the clavicle
- reinforces the acromioclavicular joint and supports the superior surface of the shoulder
coracoacromial ligament
- connects the acromion and coracoid process of the scapula
- forms a “vault” that prevents the displacement of the humeral head superiorly
coracoclavicular ligament
- main stabilizer of the acromioclavicular joint
- anchors the clavicle of the coracoid process of the scapula
glenohumeral ligament
- largest ligaments of pectoral girdle
- stabilize the glenohumeral joint, especially during adduction of the arm
- not visible in a superior view
the glenohumeral joint
- ball and socket joint between shallow glenoid cavity of the scapula and the head of the humerus
- poor fit of articular surfaces, couple with the loose fibrous capsule (joint capsule) permits extensive mobility at the expense of stability
the glenoid labrum
- stabilizing feature of glenohumeral joint
- rim of fibrocartilage that deepens the glenoid cavity improving stability
musculature of the glenohumeral joint
- group of muscles known as the rotator cuff help stabilize the glenohumeral joint
- sometimes called “dynamic ligaments” because they make up for lack of ligaments and are important in balancing the forces from movement at the shoulder joint
rotator cuff
- composed of supraspinatus, infraspinatus, teres minor and subscapulatis muscles
- biceps brachii also help stabilize joint where the long head attaches to the superior glenoid tubercle of the scapula
bursae
- fluid-filled (synovial fluid) sacs lined by synovial membrane that provide cushioning between bones, tendons and muscles and prevent friction between them
- subacromial bursa separates the superior surface of the supraspinatus tendon from the acromion, the coracoid and the coracoacromial ligament superiorly
- subdeltoid bursa separates the deep surface of the deltoid muscle from the shoulder joint
- both burase protect supraspinatus muscle from friction with overlying structures
the scapulohumeral muscles
- connect the humerus to the scapula
- stabilize glenohumeral joint
- teres major
- supraspinatus
teres major
origin: inferior part of the lateral border of the scapula
insertion: medial lip of the intertubercular sulcus of the humerus
action: extension and medial rotation of the humerus
supraspinatus
origin: supraspinatus fossa of the superior part of the scapula
insertion: greater tubercle of the humerus
action: initiates abduction of the humerus
infraspinatus muscle
origin: infraspinous fossa of the scapula, inferior to the scapular spine and superior to teres major
subscapularis muscle
origin: subscapular fossa
- anterior to the other 3 rotator cuff muscles (inferior to the coracoid process)
teres minor
origin: middle of lateral border of scapula
muscles of anterior compartment of arm
- biceps brachii, coracobrachialis and brachialis are contained in the anterior compartment
- flexion of forearm at elbow facilitated primarily by biceps brachii and brachialis
- coracobrachilis flexes the arm at the glenohumeral joint
- biceps brachii = powerful supinator of forearm
muscles of posterior compartment of arm
- triceps brachii originates from 3 heads: long head from infraglenoid tubercle of scapula, lateral and medial heads from posterior surface of humerus
- all 3 heads insert at a common tendon (triceps tendon) at the olecranon of the ulna
- elbow extension produced mainly by triceps brachii
cubital fossa
- triangular depression located at anterior surface of elbow joint
- contains important neurovascular structures (analogous to popliteal fossa)
superior border of cubital fossa
imaginary line between humeral epicondyles
medial border of cubital fossa
pronator teres
lateral border of cubital fossa
brachioradialis
contents of the cubital fossa
- the tendon of the biceps brachii
- brachial artery (which bifurcates into the ulnar and radial arteries)
- the median nerve
3 articulations of the elbow joint
- humeroradial joint
- humeroulnar joint
- superior (proximal) radioulnar joint
humeroradial joint
joint between the capitulum of the humerus and the concave upper surface of the head of the radius
humeroulnar joint
joint between the trochlea of the humerus and the trochlear notch of the ulna
superior (proximal) radioulnar joint
synovial joint between the head of the radius and the radial notch of the ulna
proximal radioulnar joint
- formed between the head of the radius and the radial notch of the ulna
annular ligament
encircles the head of the radius, holding it against the radial notch of the ulna
interosseus membrane
forms a fibrous joint that spans the space between the ulna and radius and divides the forearm into anterior and posterior compartments
distal radioulnar joint
formed between the head of the ulna and ulnar notch of the radius
muscle of superficial anterior compartment of the forearm
pronator teres
muscle of anterior intermediate compartment of forearm
flexor digitorum superficialis
muscles of anterior deep compartment fo forearm
- flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
muscles of posterior superficial compartment of forearm
- extensor digitorum
- extensor carpi radialis, longus and brevis
- extensor carpi ulnaris
divisions of posterior compartment of forearm
- superficial and deep layers
bones of wrist and hand
- collectively referred to as “carpal bones”
- arranged in 2 rows of 4
proximal row of carpal bones from lateral to medial
- scaphoid (most commonly fractured because it is the largest bone that articulates with the radius)
- lunate
- triquetrium
- pisiform
distal row of carpal bones from lateral to medial
- trapezium
- trapezoid
- capitate
- hamate (with prominent hook)
intercarpal joints
- synovial plane joints between the carpal bones
- capable of slight gliding movements
midcarpal joints
- articulation between proximal and distal rows of carpal bones
- capable of slight gliding movements
radiocarpal (wrist) joints
- a biaxial, synovial, ellipsoidal (condyloid) joint formed between the distal end of the radius and the proximal row of carpal bones (with the exception of the pisiform)
- functions in extension, flexion, abduction, adduction and circumduction
the carpal tunnel
- on the anterior surface, the carpal bones form a concavity which is covered by a bridge of deep fascia (the flexor retinaculum)
- together these structures form the carpal tunnel
what passes through the carpal tunnel?
- the median nerve
- 9 flexor tendons (4 flexor digitorum superificialis, 4 flexor digitorum profundus and flexor pollicis longus)
what are the extrinsic muscles of the hand?
- the long extensor and flexor muscles of the forearm which insert into the hand
- the extensor muscle tendons pass deep to the extensor retinaculum, a broad ligamentous sheet located at the dorsal aspect of the wrist (acts to hold the tendons in place)
what are the intrinsic muscles of the hand?
- originate and insert within the hand
- responsible for fine and skilled movements
- hypothenar muscles
- thenar muscles
- dorsal interossei muscles
- palmar interossei muscles
what is the function of the hypothenar muscles
responsible for movement of 5th digit
what is the function of the thenar muscles
responsible for the movement of the thumb
what is the function of the dorsal interossei muscles
responsible for finger abduction
what is the function of the palmar interossei muscles
responsible for finger adduction
what are the arterial arches formed by the radial and ulnar arteries
- the superficial palmar arch
- the deep palmar arch
the superficial palmar arch
- ulnar artery passes superficial to the flexor retinaculum entering the palm to form the superficial palmar arch
- medially, the arch is completed by the radial artery
- arch located superficial to the long flexor tendons of the hand
- 4 branches of the superficial palmar arch supply the medial 3 and a half fingers
the deep palmar arch
- the radial artery curves dorsally to enter the deep part of the palm as the deep palmar arch which is completed by the deep branch of the ulnar artery
- the deep palmar arch gives off branches which supply the thumb and lateral half of the second finger
from which plexus does the sensory innervation of the hand arise
brachial plexus (supplied by 3 terminal nerve branches)
ulnar nerve
cutaneous branches of the ulnar nerve provide sensation to the skin of the palmar and dorsal aspects of the medial 1 and a half digits (digits 4&5) and adjacent palm
median nerve
supplies cutaneous innervation to the skin of the lateral 2/3 of the palm, the palmar surfaces of the lateral 3 and a half digits and the dorsum of the distal halves of the same digits
radial nerve
superficial branch of the radial nerve passes from the anteriolateral aspect of the forearm to the dorsum of the hand, giving cutaneous branches to the skin of the lateral half of the dorsal aspect of the hand, the proximal portions of the dorsal aspect of digits 1, 2, 3 and the lateral half of digit 4
