Dissection - Upper Limb (bones, joints, muscles)

Question 1

The body can be grossly divided into what two major structures?

Answer 1

• the main body (head, neck, trunk)

- the appendages (upper limb and lower limb)

Question 2

The skeleton is divided into what two major parts?

Answer 2

• the axial skeleton - head, neck and trunk

- the appendicular skeleton - the limbs

Question 3

What are the general functions of the limbs?

Answer 3

• upper limb - position the hand for manipulation and grip activites
• lower limb - support body weight, locomotion, maintain balance

-not absolute

Question 4

The upper limbs are connected to the trunk by what?

Answer 4

• the left and right sternoclavicular joints which are true joint
• the left and right scapulothoraic joints, which are ‘virtual’ or ‘physiological’ joints

Question 5

The lower limbs are connected to the trunk by what?-

Answer 5

• connected by joints between the pelvis and sacrum
• the left and right sacroiliac joints
• this is a synovial joint, but is relatively immobile

Question 6

What are the regions of the upper limb?

Answer 6

• the pectoral (shoulder) girdle
• the arm
• the forearm
• the hand

Question 7

Tell me about the clavicle.

Answer 7

• the collar bone
• connects the upper limb with the trunk
• supports the scapula and the rest of the upper limb allowing greater range of movement
• the medial end joins with the thoracic wall of the trunk at the manubrium
• the lateral end joins with the scapular acromion
• movable strut has many small bony features where muscles and ligaments can attach

Question 8

What is the manubrium ?

Answer 8

-the superior part of the sternum

Question 9

What is the scapula?

Answer 9

• shoulder bone
• a triangular plate of bone with various bony features including processes, ridges, fossae which are sites of attachment for muscles and ligaments
• acromion articulates with the clavicle
• coracoid process in the superior which protrudes anteriorly
• the glenoid fossa is a shallow cup like depression in the lateral scapula, which is the socket for the ball and socket shoulder joint
• the glenoid fossa articulates with the humoral head (the proximal end of the humerus bone)
• the scapular spine is a ridge of bone divides the posterior scapula into the supraspinous and infraspinous fossa. The scapular spine’s lateral end is the acromion
• the sub scapular fossa on the anterior side is closest to the chest wall

Question 10

What is the humerus ?

Answer 10

• the largest bone of the upper limb
• articulates proximally (superiorly) with the glenoid fossa of the scapula to form the shoulder joint
• articulates distally (inferiorly) with the radius and ulna to form the elbow joint
• the various bony features are sites of attachment for muscles and ligaments
• the grooves accommodate rope-life tendons and nerves.

Question 11

What are condyles?

Answer 11

-round ends of the bone

Question 12

What is the radius and ulna?

Answer 12

• articulate at the proximal end with the condyles of the humerus
• articulate at the distal end with the proximal carpal bones of the wrist
• connected along the length of their shafts by a connective tissue layer - the interosseous membrane

Question 13

What is the interosseous membrane?

Answer 13

• connective tissue along the length of the radius and ulna shafts, fibres connecting these together
• contributes to the stability and a site of muscle attachment

Question 14

Tell me about the carpal bones

Answer 14

• 8 bones arranged in 2 rows of 4, the proximal and distal rows
• the distal ends of the radius and ulna articulate with the proximal row of carpal bones, with the exception of pisiform (a sesamoid bone)
• the proximal row of the carpals articulate with the metacarpals of the hand, which in turn articulate with the phalanges of the digits

Question 15

How many phalanges do the digits have?

Answer 15

-all digits have 3 phalanges, except the thumb which has 2.

Question 16

Overview of joint PPT

Answer 16

https://d3c33hcgiwev3.cloudfront.net/WDYiB768SFe2Ige-vChX1A_e856439a60784f808ce02078eac36036Overview-of-Joints-and-associated-structures.pptx?Expires=1579305600&Signature=FQaSYp00ZxOSdsDhvw4X7DBkNiEojM88RtwZziUsHIwHhLLNqJZl-AKHeb-CeaHu9yRYooZ88OoGZa3aTRmhLKqGlMpFZFCQDhF3fexl5jYiRMX7qdNDXZwPxSodPAV1j-HWYu7h52MkLgHZ~gBb2K1-LJ1O~DbcJrjQaxAg3Dg&Key-Pair-Id=APKAJLTNE6QMUY6HBC5A

Question 17

Joints are classified by what two things?

Answer 17

• their structural properties

- their level of mobility

Question 18

What are the structural classifications of joints?

Answer 18

• fibrous
• cartilaginous
• synovial joints

Question 19

What are fibrous joints?

Answer 19

-bones are connected by fibrous connective tissue e.g sutures of skull, syndesmosis in forearm

Question 20

What are cartilaginous joints?

Answer 20

• bones connected with cartilage e.g pubic symphysis
• primary (synchondrosis, connected by hyaline cartilage)
• secondary (symphysis, connected by fibrocartilage - mainly in the midline of the body)

Question 21

What are the synovial joints?

Answer 21

• the articulation is surrounded by an enclosing synovial capsule
• the bones are not directly connected at the joint surfaces but strengthened by surrounding structures. e.g. interphalangeal joints, articular surfaces generally covered in hyaline cartilage

3 types:

• uniaxial- movement only in one direction e.g hinge joint
• biaxial - movement in 2 different planes e.g saddle joint
• multiaxial - movement on several axes e.g ball and socket joint

Question 22

What is the epiphyseal plate?

Answer 22

• structure observes in the bones of all ages except elderly
• temporary cartilaginous joints that allow bone growth
• epiphyseal plates remain cartilaginous until bone growth ceases, when they ossify (turn to bone)

Question 23

What are the classifications of joint mobility?

Answer 23

• synarthosis - little or no mobility
• amphiarthosis - limited mobility (often fibrocartilaginous)
• diarthosis - freely mobiel (mainly joints, most synovial)

Question 24

What is the relationship between mobility and stability ?

Answer 24

• trade off

- the more mobile a joint, the less stable it usually is

Question 25

For some joints, the shape of the articulating parts of the bones would provide very poor stability on their own. Stability is provided by other structures. What are they?

Answer 25

• ligaments - collagenous connective tissue linking bones
• tendons - collagenous connective tissue between bones and muscles
• ligaments often significantly restrict movement to prevent unwanted movements that would destabilise a joint

Question 26

What is fascia?

Answer 26

-a band or sheet of connective tissue

Question 27

What is retinaculum?

Answer 27

• thickened band of deep fascia found close to a joint
• holds tendons down during muscle contraction to prevent bow-stringing
  e. g extensor retinaculum of the wrist

Question 28

What is aponeurosis?

Answer 28

• flat sheet-like structure formed from a tendon or ligament -provide broad attachment for a muscle which will distribute mechanical load over a larger area e.g biceps aponeurosis
• provide protection for underlying structures e.g palm of the hand and sole of the foot.

Question 29

What is bursa?

Answer 29

• closed sac of serous membrane, whose interior is similar to that of synovial joints
• delicate membranes secrete a lubricating fluid to their interior
• found at body sites that are subject to friction
• inflammation of a bursa (bursitis) can be extremely painful
  e. g a subcutaneous bursa at the posterior of the elbow normally prevents friction between the skin and the olecranon of the ulnar bone.

Question 30

List all of the joints in the upper limb.

Answer 30

• sterno-clavicular joint (SCJ)
• acromio-clavicular joint (ACJ)
• gleno-humeral joint (GHJ) (shoulder joint)
• scapulo-thoracic joint (STJ) (‘virtual/physiological’ joint)
• elbow joint
• wrist joint
• numerous joints in the hand

Question 31

Tell me about compartments in limb anatomy.

Answer 31

-the limb muscles are divided into compartments

Compartments tend to:

• have a distinct function
• have the same nerve supply
• same blood supply
• be separated by connective tissue septa (walls)

Question 32

List the muscular compartments in the upper limb*

Answer 32

• pectoral girdle muscles
• intrinsic shoulder muscles
• anterior arm muscles - flexors
• posterior arm muscles - extensors
• anterior forearm muscles -flexors
• posterior forearm muscles - extensors
• intrinsic hand muscles

Question 33

Tell me about the sternoclavicular joint.

Answer 33

-one of the joints of the pectoral girdle
-attaches the upper limb to the trunk
-synocial saddle joint
-joint cavity divided by fibrous articular disc
-