When are knee and elbow joints formed during embryonic development?
Limbs start out as limb buds formed by somites. 6th embryonic week marks aflexia formation of the elbow and knee joints.
What happens to leg (relative to arms) during embryonic development?
Leg rotates during embryological development.
How are limbs studied?
Limbs divided into regions.
What structures form the pectoral girdle?
Clavicle meets with scapula to form pectoral girdle.
What kind of bone is the sternum? What kind of ossification does the sternum undergo?
Flat bone formed Intramembranous ossification
What notches does the manubrium contain?
Jugular notch Clavicular notch Costal notch
What is the function of the costal notch of the manubrium?
Costal notch attaches to the first rib
What part of the manubrium does the clavicle connect to?
Sternoclavicular joint occurs at clavicular notch.
What kind of bone is the clavicle?
What kind of ossification does the clavicle undergo?
proximal and distal ends undergo endochondral ossification and shaft undergoes intramembranous ossification.
Does the clavicle have a medullary cavity? Does it have bone marrow?
What is the shape and attachment of the medial end?
Rounded sternal end. This meets the manubrium of the sternum.
What is the shape and attachment of the lateral end of the clavicle?
Lateral clavicle end is flatter and meets with the acromion process.
What is the function of the clavicle?
Clavicle acts as an S shaped strut which allows the clavicle to take the forces which acts on the upper limb and dissipates them to the midline of the body. (can be thought of as a spork (spoke, not spork you dimwit) in a wheel)
What is unique about the clavicle's ossification?
Clavicle is one of the earliest bones to start ossification and one of the last bones to complete ossification. (clavicle can be used to age skeletons)
Where is the most common site of fracture of the clavicle?
Between lateral 1/3 and medial 2/3. Common injury during a FOOSH.
What happens after the clavicle breaks? What happens if it isn't repaired?
The sternomastoid pulls the medial part upwards and the deltoid muscle pulls the lateral side of the clavicle downwards. If bone isn't fixed the fusion of the clavicle becomes crooked.
Where does the scapula sit?
Scapula lies on posterior side of rib cage and glenoid fossa faces laterally.
What are the 3 borders of the scapula?
Superior border Medial border Lateral border
What are the fossae of the scapula?
3 fossae scapula: Infraspinous fossa supraspinous fossa subscapular fossa
What structures form the suprascapular foramen?
Supra scapular notch Transverse scapular ligament.
Which part of the scapula contains the suprascapular nerve?
The suprascapular foramen on the superior border.
Where does the suprascapular artery run relative to the suprascapular foramen?
Above the transverse scapular ligament.
Where are the coracoid process and the acromion process relative to each other?
Coracoid process projects anteriorly. Acromion process projects as a continuation of the spine posteriorly.
What structures typically get fractured on the scapula?
Acromion process Coracoid process
What kind of bone is the humerus?
What shape is the head of the humerus and what are the benefits of this structure?
Head of humerus is 1/3rd of a sphere. This allows humerus to fit into glenoid socket and this allows the shoulder to be very mobile.
Where is the anatomical neck of the humerus?
Anatomical neck of the humerus separates tubercles from head.
Where is the intertubercular groove located?
Intertubercular groove is the groove between the greater and lesser tubercle.
What tendon of the arm sits in the intertubercular groove?
The long head of the biceps
Where is the surgical neck located and why is it called this?
Surgical neck lies under the tubercles and is called this because it typically gets fractured.
Where is the deltoid tuberosity found?
On the lateral aspect of the shaft of the humerus
Where are the supracondylar ridges located?
Distal end of humerus contains the supracondylar ridges.
What is the difference between the medial and lateral epicondyles?
Medial epicondyle is wider and more projecting than the lateral epicondyle.
What is the function of the trochlea and the capitulum?
Trochlea takes the ulnar and the capitulum takes the radius.
What are some common fracture sites on the humerus?
Surgical neck Midshaft Supracondylar Medial epicondyle
What structure/s is/are endangered from a surgical neck fracture?
Axillary nerve and the posterior humeral circumflex artery which pass over surgical neck of the humerus
What structure is endangered from a midshaft fracture of the humerus?
Radial nerve Deep radial artery.
What structure/s is/are endangered from a supracondylar fracture?
Median nerve Brachial artery.
What structure is endangered from a medial epicondylar fracture?
What structure surrounds the anterior and posterior compartments of the arm?
Where do the fascia of the anterior and posterior compartment meet up?
The axilla; Here the loose connective tissue that forms the armpit is found.
What structures are continuous with the fascia of the arm?
Interosseus membrane of the forearm Flexor retinaculum Extensor retinaculum
What functions does the trapezius muscle have on the upper limb?
Trapezius muscle can do different actions on the upper limb. Superior portion pulls the glenoid cavity upward but makes it face downwards. If all fibers of the trapezius contract at the same time this causes scapula to retract. Inferior portion makes glenoid cavity face upwards.
Where does the latissimus dorsi originate and insert?
Latissimus dorsi originates at many vertebrae and converges onto the intertubercula groove.
What cranial nerve innervates the trapzius muscle?
Trapezius is innervated by 11th cranial nerve (spinal accessory nerve)
Where does the levator scapulae originate and insert?
Levator scapula goes from skull + transverse process of cervical vertebrae and inserts onto superior part of the medial border.
What is the origin and insertion of the rhomboids? What is their function? Which rhomboid is minor and which is major (position relative to each other?
They originate at the spinous process of the T2 - T5 vertebrae and attach to medial border of the scapula (inferior to the spine). Rhomboids retract the scapula . Superior rhomboid is rhomboid minor and inferior rhomboid is rhomboid major.
Which cord of the brachial plexus innervates the superficial back muscles?
Where does the pectoralis major originate and insert?
Pectoralis major originate at sternum and insert onto the lip of the intertubercular groove.
Where does the pectoralis minor originate and insert?
Pectoralis minor originates at 3rd and 5th ribs and inserts onto coracoid process of the scapula.
Where does the subclavius originate and insert?
Originates at first rib and cartilage and inserts onto the clavicle (middle 3rd)
Where does the serratus anterior muscle originate and insert?
serratus anterior attaches to each rib (from 1 - 8) and inserts onto medial vertebral border of the scapula.
What is the function of the serratus anterior muscle?
Serratus anterior positions scapula against the thoracic cage. It laterally rotates scapula (protracts scapula)
What is weird about the nerve supply of the serratus anterior?
Nerve supply sits on the superficial aspect of the serratus anterior.
What causes the winging of the scapula?
.Damage to the long thoracic nerve.
Where does the deltoid muscle originate and insert?
Deltoid muscle originates at 3 positions: Clavicle Spine of the scapula Acromion process and inserts onto the deltoid tubercle of the humerus.
What is the function of the deltoid muscle?
Deltoid allows flexion, abduction, and extension of the arm.
How does the deltoid muscle function as a shunt muscle?
Deltoid works as a shunt muscles. It prevents inferior dislocation of the humerus by pulling the humeral head in its socket.
Where does teres major originate and insert and what is its function?
Origin: Posterior aspect of the inferior angle of the scapula Insertion: Medial lip of the intertubercular groove of the humerus. Function: Adducts the humerus and internally rotates humerus.
What are the rotator cuff muscles?
Supraspinatus Infraspinatus Teres Minor and subscapularis are the rotator cuff muscles (SITS muscles)
How does adhesive capsulitis typically develop?
Supraspinatus works in a tight space between coracoid and acromion process. Hypertrophy of muscles around it can cause impingement of the tendon and in time the synovial membrane and fluid and bursae can get inflamed and cause frozen shoulder (adhesive capsulitis)
What is the point of insertion of the supraspinatus and what is its function?
Supraspinatus goes to the greater tubercle of the humerus and helps start abduction. When injured this causes painful arch syndrome.
Where do the long head and the short head of the biceps originate?
Long head goes intracapsular and short head starts at scapula and converges with long head at the bicipital aponeurosis. Biceps flex the arm.
How does the biceps act as a supinator?
Biceps attaches to radius and so it also works as a supinator.
What is the function of the coracobrachialis?
Works with the biceps in flexion of the arm.
Where do the biceps muscles insert?
Radial tuberosity and bicipital aponeurosis into deep fascia on medial part of forearm
What is the origin and insertion of the brachialis muscle?
The brachialis muscle starts at the shaft of the humerus and inserts onto the ulnar deep to the bicipital apneurosis.
Where does the corachobrachialis originate and insert?
Coracobrachialis originates at coracoid process and attaches to shaft of the humerus
What is the function of the brachialis muscle?
Assists the biceps in flexion of the arm at the elbow joint.
What is the function of pectoralis minor?
Pectoralis minor lifts the thoracic cage and pulls the scapula forward. This is known as protraction.