A to Z Entries
Clare E. Milner in Functional Anatomy for Sport and Exercise, 2019
The lateral muscles of the neck are the trapezius and the sternocleidomastoid. Similar to the muscles on either side of the lumbar spine (see lumbar spine and pelvis – muscles), the action of the sternocleidomastoid muscles depends on whether one or both of them are active. Contraction of the muscle on one side of the head bends the neck laterally to the same side or rotates the head towards the opposite side. The action of both muscles together flexes the neck forwards. The trapezius is a large muscle that acts at the shoulder as well as the neck (see shoulder complex – muscles). Its role at the neck is to laterally flex the neck towards the side that is contracting, while rotating the head away from that side; trapezius extends the neck if both sides contract simultaneously.
Head and Neck
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno in Understanding Human Anatomy and Pathology, 2018
The trapezius is usually described as a part of the “superficial muscles of the back” (Plates 4.6) but evolutionarily and developmentally it is a head muscle. The trapezius and the sternocleidomastoid receive motor innervation via a cranial nerve (accessory nerve; CN XI), and originate embryo-logically from the region of the posterior branchial arches, subsequently expanding caudally to attach onto the pectoral (or shoulder) girdle (scapula and clavicle) and sternum. During their caudal expansion, they form connections with the cervical spinal nerves C3 and C4, which provide sensory innervation to them. This pattern of innervation, together with their adult attachments onto the shoulder girdle and sternum, suggest that the trapezius and sternocleidomastoid should be considered head muscles that share features with postcranial muscles. These muscles help to blur the distinction between head and trunk (see also Box 3.2). In fact, the trapezius and sternocleidomastoid played an important role in the origin and early evolution of the neck, which separated the head from the region of the upper limbs in tetrapods, that is, animals with upper and lower limbs (amphibians, reptiles, and mammals) (see Box 3.14).
Chronic Pain and Posttraumatic Headaches
Rolland S. Parker in Concussive Brain Trauma, 2016
Clinical Example (Referred pain): A middle-aged woman was in a MVA. Her car was going 50 mph. The oncoming car swerved left so that the passenger sides collided. The woman is completely amnestic. She arrived at the hospital via ambulance with cervical spine immobilization. She has not returned to work because of head pains, lower back pain, and having started to experience memory loss after the accident. She is still having problems. Her equilibrium is off; she loses balance and falls. When she came out of the hospital she could hardly stand, she was falling frequently and had a lot of nausea. She fell four to five times a day. The frequency has diminished to one to two times a day. Pain study: Pressure on the right trapezius muscle was referred to the neck. She was asked to squeeze her own shoulder and she told of pain referred into her arm. Pain was also referred to the right of the vertex from the hairline towards the occipital region. This illustrates the point that the area of experienced pain may be initiated by an unhealed injury elsewhere.
Comparison of the electromyographic recruitment of the posterior oblique sling muscles during prone hip extension among three different shoulder positions
Published in Physiotherapy Theory and Practice, 2021
Sung-Min Ha, In-Cheol Jeon
Second, the trapezius muscle is one of the muscles in the superficial back line, and is aligned with elements of the posterior oblique sling muscles (Myers, 2013). There is evidence that shoulder abduction angles greater than 110° activate lowT (Kim et al., 2013). During PHE with 125° of shoulder abduction, activation of the lowT muscles may facilitate greater co-activation of the myofascial sling muscles that stabilize the thoracic and lumbar spine. In addition, the lowT muscle fibers are oriented upward and outward, and shoulder abduction angles above 125° may help align the muscle movement lines with the muscle fiber lines (Kang et al., 2013). Shoulder extension with less than 90° of abduction contributes to anterior tilting of the scapular motion in the sagittal plane (Borstad and Ludewig, 2002). In contrast, shoulder flexion with more than 100° of shoulder abduction contributes to scapular posterior tilting in the sagittal plane during arm elevation (Borstad and Ludewig, 2002). Therefore, PHE with 125° of shoulder abduction can be performed with posterior tilting of scapular motion by lowT contraction, resulting in greater co-activation of various muscles in the posterior oblique sling muscle such as the MT and GM for serving as guy wires with lumbopelvic stability (McGill, 2015). These results demonstrate the clear effects of shoulder position on pelvic rotational movement.
Cluster subgroups based on overall pressure pain sensitivity and psychosocial factors in chronic musculoskeletal pain: Differences in clinical outcomes
Published in Physiotherapy Theory and Practice, 2019
Suzana C Almeida, Steven Z George, Raquel D. V Leite, Anamaria S Oliveira, Thais C Chaves
The points evaluated by algometry were the thenar region of the nondominant hand and the nine sites described by the American College of Rheumatology (Wolfe et al., 1990), including the following: 1) sternal border of the sternocleidomastoid muscle above the head of the clavicle; 2) midpoint of the upper trapezius muscle; 3) second rib, lateral to the costochondral junction, on the upper surface (request contraction of the pectoralis major); 4) 2–4 cm distal to the lateral epicondyle (m. brachioradialis); 5) medial knee fat, proximal to the joint interline; 6) insertion of the suboccipital muscle; 7) supraspinatus insertion above the spine of the scapula, near the upper edge; 8) superolateral quadrant of the buttock, anterior to the muscle (contraction of the gluteus maximus); and 9) posterior to the greater trochanter.
Impact of rest-break interventions on the neck and shoulder posture of symptomatic VDU operators during prolonged computer work
Published in International Journal of Occupational Safety and Ergonomics, 2018
Montakarn Chaikumarn, Nuttika Nakphet, Prawit Janwantanakul
The first hypothesis of this study was that the two active breaks compare with passive break would cause larger increases in CV and FS angles. The present study did not found significant differences in the CV and FS angles among three types of rest break. However, stretching and dynamic contraction showed a greater trend of a positive effect on the CV and FS angles for the symptomatic VDU operators. This is in line with a previous study reporting that active breaks with stretching and joint mobilization significantly improve muscular discomfort compared with passive breaks [45]. This could positively affect the joint position of the neck–shoulders in the CV and FS angles of the subjects. Furthermore, Blangsted et al. [46] reported that passive breaks are insufficient to attain complete relaxation of the trapezius muscle. As regards the neck–shoulder posture, the trapezius muscle is the main stabilizer. If the trapezius is fatigued during prolonged computer work, the CV and FS angles could be reduced and can cause increased forward head posture. This is in agreement with another study showing that increased forward head posture during VDU work caused an increase in the muscular activity in the neck–shoulder musculature to hold the head and neck in this position, which may then result in muscle fatigue and muscle imbalance [15]. In addition, this present study chose the protocol of adding a 3-min rest break after every 20-min interval because a previous study showed this to have a favourable effect on avoiding neck and shoulder muscle fatigue among symptomatic VDU operators [47].