Selected Joints

1
Selected Joints Muscular System IArchitecture

• Lecture 9

2
Shoulder Joint
Fig. 9.15

• Ligaments of the Shoulder Joint
• Glenohumeral (3)
• Transverse humeral
• Coracohumeral
• Coracoacromial
• Coracoclavicular

• Muscles of Shoulder Joint
• Rotator cuff (4 muscles)

3
Knee Joint

• Menisci Fibrocartilage articular disks
• Cruciate ligaments Anterior cruciate ligament
  and posterior cruciate ligament
• Collateral ligaments Fibular and tibial

Fig. 9.19
4
Knee Injuries and Disorders

• Football injuries
• Damage to collateral ligaments due to blow
• Torn menisci
• Torn cruciate ligaments

Figure from Clinical View on page 278
5
Properties of Muscle

• Contractility
• Ability of a muscle to shorten with force
• Excitability
• Capacity of muscle to respond to a stimulus
• Extensibility
• Muscle can be stretched to its normal resting
  length and beyond to a limited degree
• Elasticity
• Ability of muscle to recoil to original resting
  length after stretched

6
General Principles of Muscles

• Tendons Attach muscles to bones
• Aponeurosis A very broad tendon
• Muscles
• Origin or head Muscle end attached to more
  stationary of two bones
• Insertion Muscle end attached to bone with
  greatest movement
• Belly Largest portion of the muscle between
  origin and insertion
• Synergists Muscles that work together to cause a
  movement
• Prime mover Plays major role in accomplishing
  movement
• Agonist Muscle causing an action when contracts
• Antagonist A muscle working in opposition to
  agonist
• Fixators Stabilize joint/s crossed by the prime
  mover

7
Muscle Shapes
Table 10.5
8
Muscle Shapes
Table 10.5
9
Nomenclature
Fig. 10.14
10
Nomenclature
Fig. 10.14

• Example - extensor carpi radialis longus

11
Review Question

• The muscle name transversus thoracis is derived
  from a combination of its
• Size and function
• Orientation and location
• Relative length and location
• Shape and orientation
• Function and shape

12
Points to Remember

• Skeletal muscles have many shapes and in each
  instance contraction of the muscle tissue causes
  body movements through their attachments to the
  skeleton or beneath the skin.
• Understanding the meaning of the parts of a
  muscle name helps one to learn the muscle.

13
Questions?