T2 L1 Morphological plan of upper limb Flashcards
Why are most mammals quadrupedal?
Allows for locomotion and climbing
Describe some anatomical evolutions
Changes to foot, hip, knee, vertebral column, skull
Longer clavicles allowing greater range of movement
Opposable thumbs
Describe the arrangement of the upper limb from coarse to fine muscle groups
Shoulder Arm Elbow Forearm Wrist Hand
What is the interosseous membrane?
Broad thin plane of fibrous tissue which holds the radius and ulna together
Allows slight movement between the bones for pronation / supination
What movements can limbs make?
Flexion / extension Abduction / adduction Lateral / medial rotation Pronation / supination Circumduction Opposition
What movements can the glenohumeral joint make?
Extension / flexion
Abduction / adduction
Lateral (external) / medial (internal) rotation
What movements can the elbow joint make?
Extension / flexion
Pronation / supination
What movements can the wrist (radiocarpal) joint make?
Extension / flexion
Abduction / adduction
Give an example of a saddle shaped joint
Joint between 1st carpal and 1st metacarpal (carpometacarpal)
What movements can the metacarpophalangeal joint make?
Extension / flexion
Abduction / adduction
What movements can the interphalangeal joints make?
Extension / flexion
What are the 2 functional compartments?
Anterior (flexor) compartment
Posterior (extensor) compartment
What is the origin, insertion and function of pectoralis major?
Origin = sternum, medial part of clavicle, costal cartilage Insertion = lateral lip of bicipital groove Function = Adduction, flexion, medial rotation
What is the origin, insertion and function of pectoralis minor?
Origin = ribs 3,4,5 Insertion = Coracoid process Function = protraction
What is the origin, insertion and function of serratus anterior?
Origin = medial wall of thorax (upper 8 ribs) Insertion = medial edge of scapula Function = protraction
What is the origin, insertion and function of deltoid muscle?
Origin = spine of scapula, acromion, lateral 1/3 clavicle
Insertion = deltoid tuberosity of humerus
Function = abductor
- posterior fibres for extension and lateral rotation
- anterior fibres for flexion and medial rotation
What is the origin, insertion and function of teres major?
Origin = inferior angle of scapula Insertion = medial lip of intertubercular sulcus of humerus Function = adduction and medial rotation
What is the origin, insertion and function of biceps brachii?
Origin = supraglenoid tubercle, coracoid process of scapula Insertion = radial tuberosity, fascia of forearm Function = flexion, supination
What is the origin, insertion and function of coracobrachialis?
Origin = coracoid process of scapula Insertion = shaft of humerus Function = flexion
What is the origin, insertion and function of brachialis?
Origin = medial and lateral surfaces of humeral shaft Insertion = ulna tuberosity Function = flexion
What is the origin, insertion and function of triceps brachii?
Origin = infraglenoid tubercle, humerus Insertion = ulna Function = extension
Where do the flexors of the forearm mainly come from?
Medial epicondyle
Where do the extensors of the forearm mainly come from?
Lateral epicondyle
What movements can the vertebral column make?
Extension / flexion
Lateral flexion / lateral extension
Rotation
What is the function of the 4 curvatures of the vertebral column?
Bipedalism
Shock absorption
Flexibility
What is the purpose of primary kyphoses?
Allows foetus to adopt a curved posture
What is the purpose of secondary lordosis?
Important for transition from crawling to walking
What is hyperkyphoses?
Rounded back
Why is whiplash common?
Injury to anterior longitudinal ligament is common as this is the only ligament to resist hyperextension
What is the function of the intervertebral joints?
Weight bearing and strength
What is the function of the intervertebral discs?
Shock absorbers
Why does the disc thickness increase down the vertebral column?
Have to absorb more stress
What are the articulating surfaces of the intervertebral joints separated by?
Fibrocartilage
What is annulus fibrosus?
Rings of fibrocartilage (secondary cartilage)
Outer layer
Binds 2 adjacent bony surfaces together for strength
What are facet joints?
Joints between vertebral arches
What does movement of the facet joints depend on?
Joint angle
What are the movements of cervical facet joints and why?
Slight slope so extension / flexion and rotation
What are the movements of the thoracic facet joints and why?
Angle is almost vertical so only rotation
What are the movements of the lumbar facet joints?
Extension / flexion
What do the extrinsic muscles of the back do?
Move upper limbs / ribs
What do the intrinsic muscles of the back do?
Postural / move vertebral column
What is the origin, insertion and function of trapezius?
Origin = external occipital prominence, spinous process of cervical and thoracic vertebrae
Insertion = lateral part of clavicle, acromion and spine of scapula
Function = move scapula
- upper fibres = elevate scapula
- Middle fibres = retract scapula
- lower fibres = depress scapula
What is the origin, insertion and function of latissimus dorsi?
Origin = thoracolumbar fascia, spinous processes of T6-T12, iliac crest and inferior 3 ribs Insertion = bicipital groove of humerus Function = adduction, extension, medial rotation
What is the origin, insertion and function of levator scapulae?
Origin = transverse cervical process Insertion = anterior angle of scapula Function = elevate scapula
What is the origin, insertion and function of rhomboids?
Origin = thoracic and last cervical spinous processes Insertion = medial border scapula Function = retract scapula
What are the intermediate back muscles used for?
Accessory respiratory muscles that help expand chest cavity during inspiration
What are the deep muscles?
Splenus
Erector spinae
Multifidus
What are the 3 muscle blocks of erector spinae?
Spinales
Longissimus
Iliocostalis
What is the origin, insertion and function of multifidus?
Origin = transverse processes Insertion = spinous processes Function = major stabiliser of back
What is the trapezius innervated by?
11th cranial nerve
What is the innervation of the extrinsic muscles?
Anterior primary ramus
What is the innervation of the intrinsic muscles?
Posterior primary ramus
How is the mesoderm formed?
Produced through gastrulation
Invading epiblast cells travel through primitive streak to form mesoderm
What happens when the mesoderm undergoes further changes?
Forms paraxial, intermediate and lateral plate mesoderm
What does the paraxial mesoderm give rise to?
Somites
What is lateral plate mesoderm important for?
Limb development
When do limb buds appear?
As out-pocketings from body wall during week 5
What is mesenchyme made from?
Lateral plate mesoderm
What does atypical ectodermal ridge (AER) do?
Keeps cells at distal region in a state of proliferation and undifferentiated
What is spatial patterning of the limb under control of?
Hox genes
What does limb mesenchyme produce?
Connective tissue of the limbs e.g. tendons, ligaments, fascia, cartilage and bone
What happens to the limbs at week 6?
Limb extends further and flattens so hand / foot plate forms as a paddle shaped feature. Digital rays then form in this region.
Tissue between each ray undergoes programmed cell death to form fingers and toes
Where do limb muscle cells originate?
Somites
What happens to the limb muscle cells from the somite?
Delaminate from somite and migrate into limb bud then congregate close to skeletal elements
Muscle cells organise into ventral and dorsal muscle masses then further cleavage to form individual muscles of limb
What is phocomelia?
Parts of limb are absent at proximal regions
Due to lack of cell proliferation and failure of limb bud to grow
What is syndactyly?
Fusion of digits or joining of digits with soft tissue
Due to lack of cell death or cell proliferation problems
