Chapter 9: Joints; and 10, muscular system

Figure 9.2

Figure 9.4

Cartilaginous joints

Figure 9.5

Anatomy of a synovial joint

Learn joint disorders: Table 9.1

Tendon Sheaths and Bursae

• Bursa: saclike extension of joint capsule that extends between nearby structures, allowing them to slide more easily past each other

• Tendon sheaths: elongated cylinders of connective tissue lined with synovial membrane & wrapped around a tendon

The Functions of Muscles

• Movement of body parts and organ contents

• Maintain posture and prevent movement

• Communication - speech, expression & writing

• Control of openings and passageways

• Body heat production

Figure 10.1

The arrangement of fascicles affects power and range of motion that a muscle can produce.

 Range of motion:

-muscle fibers contract to about 70% of their resting length.

 -therefore, the longer the muscle fibers, the greater the range of motion.

Power: -depends on the number of fibers

Structures of Muscles

Figure 10.2

• Origin– attachment at stationary

end of muscle

• Belly– thicker, middle region of

muscle

• Insertion– attachment at mobile end

of muscle

Muscles act in groups• Agonist: prime mover.

– The muscle that produces the most force during a particular joint action.

• Antagonist: A muscle that opposes the prime mover.

– Antagonistic pairs: produce opposite effects such as flexion and extension.

• Synergist: A muscle that aids the prime mover.

• Fixator: prevents a bone from moving.

Muscle Actions during Elbow Flexion

• Prime mover (agonist) = brachialis m.

• Synergist = biceps brachii m.

• Antagonist = triceps brachii m.

• Fixator = muscle that holds scapula firmly in place such as rhomboideus m.

Figure 9.9a

Joints as lever systems

Figure 9.9b

Figure 9.8b

Figure 9.9c

Fig. 8-21a, p.335

The elbow and biceps brachii: mechanical model

Figure 9.8a

Types of synovial joints

Figure 10.7a

Figure 10.7b

The muscles of chewing and swallowing

The muscles of chewing and swallowing

Figure 10.10a

Figure 10.10b

Figure 10.17

The muscles of respiration• Primary muscles:

– Diaphragm– External intercostals– Internal intercostals

Figure 10.13

The muscles of the anterior abdomen wall

External abdominal obliqueInternal abdominal obliqueTransverse abdominalRectus abdominus

Tendons are aponeurosesRectus sheath

The muscles of the anterior abdomen

Figure 10.14

The muscles of the back 1.

Trapezius and latissimus dorsi:Primarily act on upper limb.

The muscles of the back 2.

• Erector spinae: runs from cranium to sacrum.

– Ascends and forms 3 parallel columns

– (lateral to medial)

• Iliocostalis

• Longissimus

• Spinalis

• Quadratus lumborum

The muscles of the back cont.

• Semispinalis thoracis

• Multifidus: a series of tiny muscles connecting adjacent vertebrae to each other.

The erector spinae and quadratus lumborum are enclosed in the thoracolumbar fascia, which is the origin for some abdominal and lumbar muscles.

The muscles of the pectoral girdle• Muscles acting on the pectoral girdle originate on the

axial skeleton and insert on the clavicle and scapula.

• Muscles acting on the scapula:

• Anterior group:– Pectoralis minor– Serratus anterior

Muscles acting on the scapula:• Posterior group:

– Levator scapulae– Rhomboideus minor– Rhomboideus major– Trapezius

Figure 10.21

The muscles acting on the humerus• Axial muscles: originate primarily on the axial

skeleton.– Pectoralis major– Latissimus dorsi• These are the prime movers of the shoulder joint.

• Scapular muscles: 7 muscles originate on the scapula. Tendons of 4 of these form the rotator cuff.

Axial muscles:Latissimus dorsiPectoralis major

Table 10.10b

Scapular muscles acting on the humerus– 1. Deltoid– 2. Teres major– 3. Coracobrachialis

• Rotator cuff muscles:– 4. Supraspinatus– 5. Infraspinatus– 6. Teres minor– 7. Subscapularis

Figure 10.22a

Deltoid

Figure 10.22d

Subscapularis

Coracobrachialis

Figure 10.22b

Supraspinatus

Infraspinatus

Teres minor

Teres major

Figure 9.10

Movements of the shoulder joint.

Prime movers of shoulder• Flexion: anterior deltoid, pectoralis major

• Extension: posterior deltoid, latissimus dorsi

• Abduction: lateral deltoid

• Adduction: pectoralis major, latissimus dorsi

• Medial rotation: subscapularis

• Lateral rotation: infraspinatus

Figure 9.23b

Figure 9.23c

Figure 10.22c

Figure 10.24

• Rotator cuff muscles:

– 4. Supraspinatus

– 5. Infraspinatus

– 6. Teres minor

– 7. Subscapularis

Figure 9.23d

Muscles acting on the forearm

• Muscles with bellies in the arm (brachium)– Biceps brachii– Brachialis– Triceps brachii

• Muscles with bellies in the forearm (antebrachium):– Brachioradialis– Anconeus– Pronator quadratus– Pronator Teres– Supinator

Figure 10.22a

Figure 10.22b

The elbow• Hinge (humeroulnar), Pivot (radioulnar).

• Prime movers of elbow:

• Flexors: primarily Brachialis, to a lesser extent Biceps brachii, Brachioradialis

• Extension: primarily Triceps brachii

• Pronation: primarily Pronator quadratus, assisted by Pronator teres

• Supination: Biceps brachii, Supinator

Figure 9.24a

Figure 9.24b

Figure 9.24c

Figure 9.24d

Prime movers of the elbow:

• Flexors: primarily Brachialis, to a lesser extent Biceps brachii, Brachioradialis

• Extension: primarily Triceps brachii

• Pronation: primarily Pronator quadratus, assisted by Pronator teres

• Supination: Biceps brachii, Supinator

Figure 10.22c

Figure 10.22d

Figure 10.22b

Figure 10.25

The wrist

• Intrinsic and extrinsic muscles acting on the hand.

• Flexors

• Extensors

• Carpel tunnel

Figure 9.6

Extrinsic vs intrinsicmuscles

Figure 10.27

Figure 10.28

Figure 10.29a

Figure 9.6

Figure 10.30b

Figure 10.30a

Figure 10.29d

The Hip joint

• Ball and socket

Figure 9.25b

Figure 9.25c

Figure 9.25d

The muscles acting on the hip and femur• Main anterior muscles

(flexors):

– Iliacus– Psoas

– Together form the Iliopsoas

The muscles acting on the hip and femur

• Lateral and posterior muscles (adduction and extension)– Tensor fasciae latae (not

shown)– Gluteus maximus– Gluteus medius– Gluteus minimus (not

shown)

The muscles acting on the hip and femur

• Lateral and posterior muscles– Gluteus minimus

The muscles acting on the hip and femur

• Lateral and posterior muscles– Tensor fasciae latae

The muscles acting on the hip and femur• Lateral rotators:

The muscles acting on the hip and femur

• Medial (adductor) compartment of the thigh:– Pectineus– Adductor brevis– Adductor longus– Adductor magnus– Gracilis

The muscles acting on the knee

• Anterior (extensor) compartment:

• Quadriceps femoris.– Rectus femoris– Vastus lateralis– Vastus medialis– Vastus intermedius

• Sartorius

The muscles acting on the hip and femur

• Posterior (Flexor) compartment of the thigh: the hamstring group.

• Semimembranous

• Semitendinosus

• Biceps femoris

Figure 9.28a

Figure 9.28b

Figure 9.28c

Figure 9.28d

Figure 10.37

Anterior compartment: extensors

Figure 10.38

Posterior compartment, superficial

Figure 10.39

Posterior and lateral compartments, deep.