22
23
24
25
26
27
28
29
151
First arch muscles
Second arch muscles
Somitic muscles
of head
Third arch muscles
Fourth arch muscles
Head muscles, tongue muscles exposed
Lateral view, right half of mandible removed
1 Anterior belly of digastricus
2 Mylohyoid
3 Tensor veli palatini
4 Orbicularis oculi
5 Orbicularis oris
6 Buccinator
7 Mentalis
8 Stylohyoid
9 Posterior belly of digastricus (cut)
10 Stylopharyngeus
11 Levator veli palatini
12 Superior pharyngeal constrictor
13 Middle pharyngeal constrictor
14 Inferior pharyngeal constrictor
15 Cricothyroid
16 Genioglossus
17 Hyoglossus
18 Styloglossus
19 Inferior longitudinal muscle
20 Geniohyoid
21 Mucosa of tongue
22 External acoustic meatus
23 Mastoid process
24 Thyroid cartilage
25 Trachea
26 Hyoid bone
27 Mandible (cut)
28 Zygomatic arch
29 Maxilla
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
17 16
19
20
21
22
23
24
26
27
28
29
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
17 16
19
20
21
22
23
24
26
27
28
29
18
152
The dissections on this and the opposing page are deep
dissections of the head and neck that expose the palate
and muscular wall of the pharynx and larynx (muscles
Head Muscles
that arise from the third, fourth, and sixth pharyngeal arches). These are the deepest muscles of
the head and neck, and they form the muscular walls of the upper end of the embryonic gut tube.
The dissection below depicts the posterior wall of the pharynx. On the opposing page the pharyngeal wall has been sectioned to reveal the inside of the palate and larynx from behind.
First arch muscles
Second arch muscles
Third arch muscles
Fourth arch muscles
Head muscles, posterior wall of pharynx exposed
Posterior view, cervical vertebrae and occipital bone removed
1
2
3
4
5 6
10
11
12
26
28
1
2
3
4
5 6
10
11
12
26
28
153
First arch muscles
Second arch muscles
Third arch muscles
Fourth arch muscles
Sixth arch muscles
Somitic muscles
of head
Head muscles, posterior wall of pharynx cut and refl ected
Posterior view, cervical vertebrae and occipital bone removed
1 Masseter
2 Medial pterygoid
3 Lateral pterygoid
4 Stylohyoid
5 Posterior belly of digastricus
6 Stylopharyngeus
7 Levator veli palatini
8 Palatopharyngeus
9 Musculus uvulae
10 Superior pharyngeal constrictor
11 Middle pharyngeal constrictor
12 Inferior pharyngeal constrictor
13 Salpingopharyngeus
14 Posterior crico-arytenoid
15 Oblique arytenoid
16 Transverse arytenoid
17 Styloglossus
18 Pharyngotympanic tube
19 Bony nasal septum
20 Palatine tonsil
21 Tongue
22 Epiglottis
23 Cricoid cartilage
24 Esophagus
25 Trachea
26 Greater cornu of hyoid bone
27 Aryepiglottic fold
28 Pharyngobasilar fascia
1
2
4
5
6
7
8
9
10
11
12
13 13
14
15
16
17
19
20
21
22
23
24
25
27
18
1
2
4
5
6
7
8
9
10
11
12
13 13
14
15
16
17
19
20
21
22
23
24
25
27
18
154
Sectional anatomy broadens perspective and showcases anatomical relationships in ways that are not possible to achieve by dissection alone. The frontal and
parasagittal sections on these pages depict and clarify the relationships of many
of the head muscles and show the relationships these muscles have with other
structures of the head.
Head Muscles
First arch muscles
Second arch muscles
Somitic muscles
of head
Head muscles, frontal section through orbits, nasal cavity, and oral cavity
Posterior view
1
2
3
4
5
8
9
11
48 48
49
18
20
22 21
23
24
25
26
27
28
29
30
47
32
33
46
45
44
43
41
42
40
40
19
1
2
3
4
5
8
9
11
48 48
24
25
26
27
28
29
30
47
32
46
45
44
43
40
155
Head muscles, parasagittal section through oral cavity and pharynx
Posterior view, section is 1.2 cm lateral to the midline
First arch muscles Second arch muscles Fourth arch muscles Somitic muscles
of head and neck
1 Temporalis
2 Masseter
3 Anterior digastricus
4 Mylohyoid
5 Frontal belly of occipitofrontalis
6 Orbicularis oris
7 Transversus menti
8 Risorius
9 Buccinator
10 Mentalis
11 Platysma
12 Palatopharyngeus
13 Musculus uvulae
14 Superior pharyngeal constrictor
15 Middle pharyngeal constrictor
16 Inferior pharyngeal constrictor
17 Salpingopharyngeus
18 Superior rectus
19 Inferior rectus
20 Medial rectus
21 Lateral rectus
22 Superior oblique
23 Levator palpebrae superioris
24 Genioglossus
25 Hyoglossus
26 Superior longitudinal muscle
27 Inferior longitudinal muscle
28 Transversus muscle
29 Vertical muscle
30 Geniohyoid
31 Longus capitis
32 Hard palate
33 Mandible
34 Occipital bone
35 Atlas
36 Axis
37 Intervertebral disc
38 Hyoid bone
39 Epiglottis
40 Frontal sinus
41 Frontal lobe of cerebrum
42 Periorbital fat
43 Ethmoidal air cells
44 Superior nasal conchae
45 Middle nasal conchae
46 Inferior nasal conchae
47 Bony nasal septum
48 Maxillary sinus
49 Optic nerve
50 Occipital condyle
51 Torus tubarius of
pharyngotympanic tube
4
6
6
7
10
11
12
13
14
15
16
17
24
26
51
28
30
31
32
33
34
35
36
38
37
39
50
4
6
6
7
10
11
12
13
14
15
16
17
24
26
51
28
30
31
32
33
34
35
36
38
37
39
50
156
The dissection on this page exposes the deepest of the head muscles, those of
the sixth pharyngeal arch. This group, found within the wall of the larynx, is the small
series of muscles that are responsible for sound production. Contractions of these
Head Muscles
muscles vary the tension on the vocal folds and adjust the size of the rima glottidis. A cut anterior portion of the cricothyroid
is also visible; however this muscle is actually the anterior continuation of the inferior pharyngeal constrictor and develops
from the fourth pharyngeal arch.
1 Posterior crico-arytenoid
2 Lateral crico-arytenoid
3 Thyro-arytenoid
4 Thyro-epiglottic part of thyro-arytenoid
5 Oblique arytenoid
6 Ary-epiglottic part of oblique arytenoid
7 Transverse arytenoid
8 Cricothyroid (cut)
9 Hyoid bone
10 Epiglottis
11 Thyroid cartilage (cut)
12 Cricoid cartilage
13 Trachea
14 Thyrohyoid membrane
Dissection of the larynx, right lamina and horns removed
Posterolateral view
Fourth arch muscle
Sixth arch muscles
1
2
3
4
5
6
7
8
9
10
11
11
12
12
13
14
1
2
3
4
5
6
7
8
9
10
11
11
12
12
13
14
Th e trunk, which
is defi ned by the span of the vertebral column, includes
the neck (span of the cervical vertebrae), the thorax
(span of the thoracic vertebrae), the abdomen (span
of the lumbar vertebrae), and the pelvis (span of
the sacral vertebrae). Th e muscles of the trunk are
the most primitive muscles in the vertebrate
body. Th is series of muscles arises as epithelial
migrations from the myotomes of the embryonic
somites and forms a distinct muscle pattern
throughout the length of the trunk. Th e trunk
muscle pattern has two distinct subdivisions, the
epaxial muscles and the hypaxial muscles, which
are separated by a transverse intermuscular septum. Th e epaxial muscles, situated posterior to the
vertebral axis, are the extensor muscles of the vertebral
column that develop from the epimere of the myotomes.
Th e dorsal rami of the spinal nerves innervate these muscles.
Th e hypaxial muscles, positioned primarily anterior and lateral to
the vertebral axis, develop from the hypomere of the myotomes
and are supplied by the ventral rami of the spinal nerves.
Th e epaxial muscles form a number of muscle layers that anatomists typically describe as a series of groups. From superfi cial to deep
the groups are the spinotransversales muscles, the erector spinae muscles,
the transversospinales muscles, and the deepest groups (most of which
are intersegmental) consisting of the interspinales, intertransversarii,
and suboccipital muscles.
Th e hypaxial muscles form a distinct pattern throughout the trunk
wall. Th is pattern consists of a subvertebral musculature (positioned on the
anterior and lateral aspect of the vertebral bodies), a four-layered lateral
wall of muscles situated on the lateral aspect of the trunk wall, and a
ventral strap of musculature on the anterior trunk wall.
Th e photos in this chapter clearly depict the trunk muscles and the
patterns outlined above.
10 Trunk Muscles
Find more information
about the muscles of the
trunk in
157
REAL ANATOMY
158
span the entire length of the vertebral column to the posterior aspect of the occipital bone. They comprise the
intrinsic muscles of the vertebral column, which are often referred to as the “true back muscles.” The vertebral
extensors form four distinct muscle groups. These groups are, from superfi cial to deep, the spinotransversales (splenius muscles), the erector spinae, the transversospinales (three layers — the semispinalis,
multifi dus, and rotatores layers), and the intersegmental muscles. However, each of the four groups does not
extend the entire length of the vertebral column, and in some regions not all four layers are represented.
All epaxial muscles receive a nerve supply from the dorsal (posterior) rami of the spinal nerves.
The epaxial muscles, or vertebral extensors, develop on the
dorsal side of the vertebral column and skull. These muscles
arise from the myotomal epimere of all the trunk somites and
Epaxial Muscles
Dissection of epaxial musculature
Posterior view
Epaxial Muscle Layers
Spinotransversales — Splenius layer
Erector spinae layer
Transversospinalis — Semispinalis layer
Transversospinalis — Multifidus layer
Transversospinalis — Rotatores layer
Deep intersegmental layer
Vertical muscle subdivisions within muscle layers
Capitis Muscles
Splenius capitis
Erector spinae capitis
Longissimus capitis
Spinalis capitis
Transversospinales capitis
Semispinalis capitis
Suboccipitales
Rectus capitis posterior major
Rectus capitis posterior minor
Obliquus capitis superior
Obliquus capitis inferior
Cervical Muscles
Splenius cervicis
Erector spinae cervicis
Iliocostalis cervicis
Longissimus cervicis
Spinalis cervicis
Transversospinales cervicis
Semispinalis cervicis
Multifidus cervicis
Rotatores cervicis
Interspinales cervicis
Intertransversarii posteriores cervicis medialis
Thoracic Muscles
Erector spinae thoracis
Iliocostalis thoracis
Longissimus thoracis
Spinalis thoracis
Transversospinales thoracis
Semispinalis thoracis
Multifidus thoracis
Rotatores thoracis
Interspinales thoracis
Intertransversarii thoracis
Levatores costarum
Lumbar Muscles
Erector spinae lumborum
Iliocostalis lumborum
Transversospinales lumborum
Multifidus lumborum
Rotatores lumborum
Interspinales lumborum
Intertransversarii lumborum medialis
1
2
3
4
5
6
7
8
9
12
13
15
18
1
2
3
4
5
6
7
8
9
12
13
15
18
159
The spinotransversales muscles are the superfi cial-most
Dissection of splenius and erector spinae muscles
Posterior view
Splenius Musculature
1 Splenius capitis muscle
2 Splenius cervicis muscle
Other Muscles and Structures
3 Iliocostalis muscle
4 Longissimus muscle
5 Spinalis muscle
6 Semispinalis muscle
7 Multifidus muscle
8 Levatores costarum muscle
9 Intertransversarii muscle
10 Posterior scalene muscle
11 External intercostal muscle
12 Internal intercostal muscle
13 Quadratus lumborum muscle
14 External oblique muscle
15 Transversus abdominis muscle
16 Gluteus maximus muscle
17 Fascia of gluteus medius muscle
18 Supraspinous ligament
19 Nuchal ligament
Spinotransversales Muscles
epaxial muscles and are only present in the superior half of the vertebral column. This group is comprised of
two named muscles — the splenus capitis and splenius cervicis. They span from the midthoracic region to the
base of the occipital bone. As their name suggests, the fi bers attach to the spinous processes of the vertebrae
and course laterally to attach to the vertebral transverse processes. These fl at bands of muscle are primary
extensors of the upper vertebral column and head.
1
2
3
4
5
6
10
11
14
16
17
18
19
1
2
3
4
5
6
10
11
14
16
17
160
The erector spinae muscles comprise Erector Spinae Muscles the second layer of epaxial muscles.
Dissection of erector spinae muscles
Posterior view
Dissection of erector spinae muscles
Posterolateral view
Unlike the splenius muscles, the erector spinae muscle group spans the entire length of the vertebral
column. The erector spinae is divided into three parts, which from medial to lateral are the spinalis muscle,
the longissimus muscle, and the iliocostalis muscle. This strong group of epaxial muscles consists of muscle
fi bers that course vertically and somewhat laterally as they span multiple vertebral levels. They function as
primary extensors of the vertebral column.
Erector Spinae and Semispinalis Musculature
1 Iliocostalis lumborum muscle - lumbar part
2 Iliocostalis lumborum muscle - thoracic part
3 Iliocostalis cervicis muscle
4 Longissimus thoracis muscle
5 Longissimus cervicis muscle
6 Longissimus capitis muscle
7 Spinalis thoracis muscle
8 Spinalis cervicis muscle
9 Spinalis capitis muscle
10 Semispinalis thoracis muscle
11 Semispinalis cervicis muscle
12 Semispinalis capitis muscle
Other Muscles and Structures
13 Multifidus muscle
14 Levatores costarum muscle
15 External intercostal muscle
16 Internal intercostal muscle
17 Middle scalene muscle
18 Nuchal ligament
19 Trapezius muscle
20 Rhomboideus major muscle
21 Latissimus dorsi muscle
22 Infraspinatus muscle
23 Teres major muscle
24 Deltoid muscle
25 Triceps muscle
1
2
3
4
4
5
5
6
6
7
8
8
9
11
12
12
15
15
17
17
18
18
11
1
2
3
4
4
5
5
6
6
7
8
8
9
11
12
12
15
15
17
17
18
18
11
161
Dissection of semispinalis muscles
Posterior view
Dissection of semispinalis muscles
Lateral view
Dissection of semispinalis layer on left and limb muscles on right
Posterolateral view
The transversospinales
muscles form the third
layer of epaxial muscles. This deeper layer of muscles has shorter muscle fi bers, on average, than its two
superfi cial counterparts, and the fi bers angle from lateral (transverse processes) to medial (spinous processes)
as they course from sacrum to cranium. Within this group there are three muscles — the semispinalis, multifi dus, and the rotatores muscles. The more superfi cial semispinalis muscle is depicted on this page.
Transversospinales Muscles
9
10
12
12
12
13
14
14
15
15
16
18
19
20
21
22
23
24
25
9
10
12
12
12
13
14
14
15
15
16
18
19
20
21
22
23
24
25
162
The multifi dus layer of the
transversospinales musculature is highlighted on
Transversospinales Muscles
Dissection of multifi dus and intersegmental muscles
Posterolateral view
Dissection of multifi dus muscles
Posterior view
this page, and the deeper rotatores are evident on the opposite page along with the deeper intersegmental
muscles. The multifi dus muscles span three to fi ve vertebral levels in their span from the sacrum to the
second cervical vertebra, while the deepest member, the rotatores, typically span only one to two vertebrae.
The transversospinales muscles assist their more superfi cial counterparts with extension of the vertebral
column and play important roles in the maintenance of posture.
1
1
2
3
4
5 6
7
10
11
11
12
13
14
15
16
17
18
20
21
22
23
24 25
26
27
1
1
2
3
4
5 6
7
10
11
11
12
13
14
15
16
17
18
20
21
22
23
24 25
26
27
19
163
Dissection of upper deep intersegmental muscles on left
Posterior view
Multifidus, Rotatores, and Intersegemental Muscles
1 Multifidus lumborum muscle
2 Multifidus thoracis muscle
3 Multifidus cervicis muscle
4 Rectus capitis posterior major muscle
5 Rectus capitis posterior minor muscle
6 Obliquus capitis superior muscle
7 Obliquus capitis inferior muscle
8 Rotatores cervicis muscle
9 Rotatores thoracis muscle
10 Levatores costarum muscle
Other Muscles and Structures
11 Semispinalis cervicic muscle
12 Medial lumbar intertransversarii muscle
13 Nuchal ligament
14 External oblique muscle
15 Transversus abdominis muscle
16 Quadratus lumborum muscle
17 External intercostal muscle
18 Internal intercostal muscle
19 Middle scalene muscle
20 Trapezius muscle
21 Deltoid muscle
22 Latissimus dorsi muscle
23 Infraspinatus muscle
24 Teres major muscle
25 Rhomboideus major muscle
26 Triceps muscle
27 Posterior digastricus msucle
28 Auricularis posterior muscle
29 Transversus nuchae muscle
The small intersegmental muscles —
the interspinales muscles, intertransversarii muscles, levatores costarum,
and subocciptal muscles — in general span a single intervertebral joint. The interspinales and intertransversarii muscles contribute little to any signifi cant vertebral movements. They contain large numbers of
sensory neurons within their muscultendinous fasciculi. These spindle-like sensory receptors in the muscles monitor muscle tension. These small muscles, with their poor mechanical advantage, probably function as receptors that monitor the regional movements of the vertebral column and supply feedback that
infl uences the action of the larger surrounding muscles. Associated deep in the junction of the cranium and
vertebral column are the four suboccipital muscles. The suboccipital muscles are homologous to the other
deep muscles at more inferior vertebral levels, but are developmentally modifi ed and enlarged to function
with their specialized vertebral counterparts — the axis, atlas, and occipital bone.
Intersegmental Muscles
3
4
5
6
7
8
9
No comments:
Post a Comment
اكتب تعليق حول الموضوع